What the verse is referring to is the rapture/resurrection, because when Jesus leaves heaven to come for the rapture/resurrection event - the signal to do so come from the Father. Evident from 1Thessalonians4:14. Jesus does not do it on his own prerogative.
14 For if we believe that Jesus died and rose again, even so them also which sleep in Jesus will God bring with him.
I find it unreasonable to assume that the day and hour which no one but the Father knows, that this is involving the beginning of the great tribulation. Or just as unreasonable, the way some Preterists apply it to be involving 70 AD. As if the great tribulation, and or the events of 70 AD, are more relevant than His coming involving the day of the Lord. Of course though, the way some of you interpret these things, His coming involving the day of the Lord is meaning the great tribulation, and or is meaning the events of 70 AD.
Except the following verse alone debunks any of that.
Matthew 24:27 For as the lightning cometh out of the east, and shineth even unto the west; so shall also the coming of the Son of man be.
This verse undeniably proves that His coming in any sense is not before or during anything recorded in Matthew 24:15-26, it is after. And in the event this is not ample proof alone, though it clearly should be, there is this to add to it as well, therefore, further proving no coming of Jesus in any sense takes place before or during the events involving verses 15-26.
Matthew 24:23
Then if any man shall say unto you, Lo, here is Christ, or there; believe it not.
24 For there shall arise false Christs, and false prophets, and shall shew great signs and wonders; insomuch that, if it were possible, they shall deceive the very elect.
25 Behold, I have told you before.
26
Wherefore if they shall say unto you, Behold, he is in the desert; go not forth: behold, he is in the secret chambers; believe it not.
But let's just ignore any of that, though. IOW, let's just totally disregard what Jesus plainly and undeniably said here.