The resurrection was not something that was available to them in "this age" (the Transition period, 30 to 70 AD) but would be available to them in "that age" (the New Covenant age), implying that the resurrection would occur at the beginning of the New Covenant age.

The resurrection was to happen at the end of the Jewish age, the Old Covenant age. We know that this happened in 70 AD with the destruction of the Jewish temple. To be resurrected was to be given eternal life and to be in the presence of God.

We must understand that those saints who lived in the transition time did not have salvation, justification, or eternal life in its consummated form. Notice what Paul says:

Philippians 3:12 (NKJV) Not that I have already attained, or am already perfected; but I press on, that I may lay hold of that for which Christ Jesus has also laid hold of me.
What was it that Paul had not yet attained? The Greek word used here for "attained" is lambano. It means: "to receive, to grasp, to seize, to acquire." Paul is saying, "I don't have it yet." What is it that he doesn't have yet? The verb lambano is transitive, but the object is not expressed. Is it the resurrection that he mentioned in verse 11 that he has not attained? Yes, the resurrection is included, but it is more than that, Philippians 3:4-11 are a unit speaking of justification. The key verse being:

Philippians 3:9 (NKJV) and be found in Him, not having my own righteousness, which is from the law, but that which is through faith in Christ, the righteousness which is from God by faith;
Is Paul is saying that his justification had not yet been consummated? I think so. That would mean that eternal life had not been consummated. That might not fit your theology, but it fits the context of what Paul has been talking about. Paul was saying, "Not that I have already attained, or have already been justified."

Jesus Christ took our sin and bore its penalty on the cross, and he gives us his righteousness.

2 Corinthians 5:21 (NKJV) For He made Him who knew no sin to be sin for us, that we might become the righteousness of God in Him.

We have been declared righteous by God for all eternity. It will never be reversed or changed. Christ's righteousness has been imputed to our account. Justification involves the imputation of Christ's righteousness. But at the time of Paul's writing, righteousness was still a hope. Now, you might ask, "Didn't Paul and the New Testament saints already have the righteousness of God?" Yes and no. The futuristic perspective of God's righteousness was clearly expressed by Paul.

Galatians 5:5 (NKJV) For we through the Spirit eagerly wait for the hope of righteousness by faith.
If righteousness was already a fulfilled or completed event, Paul made a big mistake in making "righteousness" by faith a matter of hope. You don't hope for what you have.

Romans 8:24-25 (NKJV) For we were saved in this hope, but hope that is seen is not hope; for why does one still hope for what he sees? 25 But if we hope for what we do not see, we eagerly wait for it with perseverance.
If righteousness was a present reality, why would Paul hope for it? But Paul also talks as though it was a present possession.

Romans 4:5 (NKJV) But to him who does not work but believes on Him who justifies the ungodly, his faith is accounted for righteousness,
Did Paul have Christ' righteousness or was it still future to him? Yes! He had it, but it was also still future to him. How can this be?

Paul lived in what the Bible calls the "last days"- they were the last days of the Old Covenant. Those "last days" began at the time of Christ and ended at AD 70 when the Jewish temple was destroyed. We now live in what the Bible calls "the age to come, "which is the New Covenant age. The forty year period, from Pentecost to Holocaust, was a time of transition from the Old Covenant to the New Covenant. In this transition period, the New Covenant had been inaugurated but not consummated. It was a time of "ALREADY BUT NOT YET."

Galatians 5:5 (NKJV) For we through the Spirit eagerly wait for the hope of righteousness by faith.
The words translated: "eagerly wait" are the Greek word apekdechomai. This Greek word is only used seven times in the New Testament, and every one of them is in reference to the Second Coming. Thus, righteousness comes at the second coming.

Salvation was not a completed event in the lives of the first century believers, it was their hope, they looked forward to its soon arrival.

Romans 13:11-12 (NKJV) And do this, knowing the time, that now it is high time to awake out of sleep; for NOW OUR SALVATION IS NEARER than when we first believed. 12 The night is far spent, the day is at hand. Therefore let us cast off the works of darkness, and let us put on the armor of light.
He equates their salvation with the "day" which was at hand, referring to the day of the Lord. "Knowing the time" is the Greek word kairos, it means: "season, a special critical strategic period of time." It is used of a season of great importance in redemptive history. The completion of redemptive history was at hand, and with it would come salvation.

Peter also states that their salvation was not yet complete:

1 Peter 1:5 (NKJV) who are kept by the power of God through faith for salvation ready to be revealed in the last time.
Salvation was ready to be revealed, when? In the last time, which would happen at the return of Christ.

1 Peter 1:7 (NKJV) that the genuineness of your faith, being much more precious than gold that perishes, though it is tested by fire, may be found to praise, honor, and glory at the revelation of Jesus Christ,
In this same way, "eternal life" was not a present possession, but a hope. Remember the "already but not yet" character of the transition period. They had eternal life, but it would not be theirs in fact until the Lord returned.

Titus 3:5-7 (NKJV) not by works of righteousness which we have done, but according to His mercy He saved us, through the washing of regeneration and renewing of the Holy Spirit, 6 whom He poured out on us abundantly through Jesus Christ our Savior, 7 that having been justified by His grace we should become heirs according to THE HOPE OF ETERNAL LIFE.
Again, you don't hope for what you already have.

Jude 1:21 (NKJV) keep yourselves in the love of God, looking for the mercy of our Lord Jesus Christ unto eternal life.
I like how the NIV show it:

Jude 1:21 (NIV) Keep yourselves in God's love as you wait for the mercy of our Lord Jesus Christ to bring you to eternal life.
They had the hope of eternal life (already), but they did not have it as a present possession (not yet). Eternal life was something that was to come to them at the Second Coming, in the "age to come."

Mark 10:29-31 (NKJV) So Jesus answered and said, "Assuredly, I say to you, there is no one who has left house or brothers or sisters or father or mother or wife or children or lands, for My sake and the gospel's, 30 "who shall not receive a hundredfold NOW IN THIS TIME; houses and brothers and sisters and mothers and children and lands, with persecutions; and IN THE AGE TO COME, ETERNAL LIFE. 31 "But many who are first will be last, and the last first."
Eternal life was a condition of the age to come.

The incompleteness of believers during the transition period, 30-70 AD, does not contradict Paul's affirmation, "Ye are complete in Him" (Colossians 2:10). The certain completeness of Christ's work was the basis and confidence of the transformation already at work, with the future fullness drawing near.

I think that it is safe to say that most believers think redemption was completed at the cross. But this is not what the Bible teaches, redemption is tied to the second coming.

Luke 21:27-28 (NKJV) "Then they will see the Son of Man coming in a cloud with power and great glory. 28 "Now when these things begin to happen, look up and lift up your heads, because your redemption draws near."
When Christ returned, he brought redemption. As long as the Old Covenant existed, the believers were not perfect and did not have access to God.

Hebrews 9:8-10 (NKJV) the Holy Spirit indicating this, that THE WAY INTO THE HOLIEST OF ALL WAS NOT YET MADE MANIFEST WHILE THE FIRST TABERNACLE WAS STILL STANDING. 9 It was symbolic for the present time in which both gifts and sacrifices are offered which cannot make him who performed the service PERFECT in regard to the conscience; 10 concerned only with foods and drinks, various washings, and fleshly ordinances imposed until the time of reformation.
Under the Old Covenant, they were never made perfect. And because they were not perfect, they could not enter God's presence. The incompleteness of what they had is seen in the fact that even though they had eternal life, they still needed to be raised up at the last day.

John 6:40 (NKJV) "And this is the will of Him who sent Me, that everyone who sees the Son and believes in Him may have everlasting life; and I will raise him up at the last day."
John 6:44 (NKJV) "No one can come to Me unless the Father who sent Me draws him; and I will raise him up at the last day.
John 6:54 (NKJV) "Whoever eats My flesh and drinks My blood has eternal life, and I will raise him up at the last day.
Remember, resurrection is: "being brought into the presence of God."

What the saints had in the transition period was the down payment of the perfection that was to come.

Ephesians 1:13-14 (NKJV) In Him you also trusted, after you heard the word of truth, the gospel of your salvation; in whom also, having believed, you were sealed with the Holy Spirit of promise, 14 WHO IS THE GUARANTEE OF OUR INHERITANCE UNTIL THE REDEMPTION OF THE PURCHASED POSSESSION, to the praise of His glory.
The word "guarantee" is the Greek word arrhabon, which means: "a pledge, i.e. part of the purchase-money or property given in advance as security for the rest:- earnest." We see this same idea in:

2 Corinthians 1:22 (NKJV) who also has sealed us and given us the Spirit in our hearts as a guarantee.
2 Corinthians 5:5 (NKJV) Now He who has prepared us for this very thing is God, who also has given us the Spirit as a guarantee.
The transition saints had in pledge what we now have. They had a guarantee of what was to come. We have it all.

Well, if the transition saints did not go to heaven, then what does Paul mean in:

2 Corinthians 5:8 (NKJV) We are confident, yes, well pleased rather to be absent from the body and to be present with the Lord.
Philippians 1:23 (NKJV) For I am hard pressed between the two, having a desire to depart and be with Christ, which is far better.
I think that if you study the context of these two verses, you will see that Paul was talking about himself in the Philippian passage and in the Corinthian passage the "we" most likely refers to Paul, Timothy and Silas. Paul is saying here that if he or his companions died, they would go directly to heaven.

Could Paul go to heaven apart from the resurrection? No, but Paul knew that if he died for the witness of Christ and the word of God, he would be part of the first resurrection. During the transition period, those believers who died a martyr's death were part of the first resurrection. Let's look at Revelation 20.

Revelation 20:4 (NKJV) And I saw thrones, and they sat on them, and judgment was committed to them. Then I saw the SOULS OF THOSE WHO HAD BEEN BEHEADED FOR THEIR WITNESS TO JESUS AND FOR THE WORD OF GOD, who had not worshiped the beast or his image, and had not received his mark on their foreheads or on their hands. And THEY LIVED AND REIGNED WITH CHRIST FOR A THOUSAND YEARS.
These are clearly martyred believers from the transition period. They didn't worship the beast or take his number.

Revelation 20:5 (NKJV) But the rest of the dead did not live again until the thousand years were finished. This is the first resurrection.
No matter what your theological persuasion, there is a problem in this verse. If those of verse 4 lived and reigned with Christ for a thousand years, then how can those of verse 5 be the first resurrection? They can't be. The simple solution here is to see that they put the verse number in the wrong place. Verse 5 is a parenthesis that he will take up later in the chapter. It should read like this:

Revelation 20:5 (NKJV) But the rest of the dead did not live again until the thousand years were finished.
So the martyrs lived and reigned with Christ during the transition period (the thousand years) but the rest of the dead, everyone else who died, did not live again until the end of the transition period. Let's leave verse 5 out and read from 4 to 6.

Revelation 20:4 (NKJV) And I saw thrones, and they sat on them, and judgment was committed to them. Then I saw the souls of those who had been beheaded for their witness to Jesus and for the word of God, who had not worshiped the beast or his image, and had not received his mark on their foreheads or on their hands. And they lived and reigned with Christ for a thousand years. 6 This is the first resurrection. Blessed and holy is he who has part in the first resurrection. Over such the second death has no power, but they shall be priests of God and of Christ, and shall reign with Him a thousand years.
So, the martyrs of the transition period went to heaven as part of the first resurrection. But everyone else went at the general resurrection at the end of the age. These first resurrection martyrs went to Heaven, but they were not in the Holiest of all, the presence of God, until the temple was destroyed in AD 70.

Hebrews 9:8 (NKJV) the Holy Spirit indicating this, that the way into the Holiest of All was not yet made manifest while the first tabernacle was still standing.
Then at AD 70, when Christ returned, the believers in Hades (Old Testament saints and transition saints) were resurrected into the presence of God, and those in heaven went into the presence of God.

When Paul was comforting the Thessalonians about their deceased loved ones, notice what he said:

1 Thessalonians 4:13-17 (NKJV) But I do not want you to be ignorant, brethren, concerning those who have FALLEN ASLEEP, lest you sorrow as others who have no hope. 14 For if we believe that Jesus died and rose again, even so God will bring with Him those who sleep in Jesus. 15 For this we say to you by the word of the Lord, that we who are alive and remain until the coming of the Lord will by no means precede THOSE WHO ARE ASLEEP. 16 For the Lord Himself will descend from heaven with a shout, with the voice of an archangel, and with the trumpet of God. AND THE DEAD IN CHRIST WILL RISE FIRST. 17 Then we who are alive and remain shall be caught up together with them in the clouds to meet the Lord in the air. And thus we shall always be with the Lord.
Paul doesn't say, "Don't worry about your loved ones who recently died, they're in heaven. Remember what I taught you, 'to be absent from the body is to be present with the Lord.'" What Paul did say was at the second coming their dead loved ones would "rise," they would be resurrected.

Now if there hasn’t been a resurrection from Hades then you're claiming Christ has not destroyed death, when if fact were told He did.

2 Timothy 1:10 NIV but it has now been revealed through the appearing of our Savior, Christ Jesus, who has destroyed death and has brought life and immortality to light through the gospel.

Hosea 13:14 ESV
I shall ransom them from the power of Sheol;
I shall redeem them from Death.
O Death, where are your plagues?
O Sheol, where is your sting?
Compassion is hidden from my eyes.

1 Corinthians 15:55 ESV
“O death, where is your victory?
O death, where is your sting?”

Christ's victory over Sheol/Hades was the sting of death, which was defeated.

Adapted in part from: David Curtis