Thanks for your question.
Luke 17:37 And they answered and said unto him, Where, Lord? And he said unto them, Wheresoever the body is, thither will the eagles be gathered together.
You are not alone in being confused over Luke 17:37. This is the way I understand it.
In Luke 17:20,21 The Pharisees ask Jesus to tell them when the Kingdom of God will come. “And when he was demanded of the Pharisees, when the kingdom of God should come, he answered them and said, The kingdom of God cometh not with observation: Neither shall they say, Lo here! or, lo there! for, behold, the kingdom of God is within you.”
It is obvious from other scripture that the kingdom of God will come at the day God has appointed; but as far as the people of that day were concerned, they would not live to see it. To have their part in it they needed to believe the Gospel of the kingdom that Jesus was preaching.
So whether we think the Greek translated ‘within you’ means ‘within you’ or ‘among you’ the end result is the same. The gospel of the kingdom was being preached in their midst (among them) and if they wouldn’t believe and take it into their hearts (within them) and live accordingly they would not enter the kingdom of God. That some of them will be raised from the dead to see the kingdom of God and be rejected is clearly taught in Luke 13:28,29 “There shall be weeping and gnashing of teeth, when ye shall see Abraham, and Isaac, and Jacob, and all the prophets, in the kingdom of God, and you yourselves thrust out. And they shall come from the east, and from the west, and from the north, and from the south, and shall sit down in the kingdom of God”.
He tells his disciples that in their lifetime they would want to see the return of Christ (which begins the establishment of the kingdom of God) and not see it. Luke 17:22 “And he said unto the disciples, The days will come, when ye shall desire to see one of the days of the Son of man, and ye shall not see it.”
He says that there will be deceivers who would say that Christ had returned here or there but they were not to believe them Luke 17:23 “And they shall say to you, See here; or, see there: go not after them, nor follow them”
When Jesus does return all his disciples will know it. Luke 17:24 “For as the lightning, that lighteneth out of the one part under heaven, shineth unto the other part under heaven; so shall also the Son of man be in his day.”
Those that are alive when Christ returns are not to suppose that someone will come with a message telling them to go and meet him in a particular place. Paul explains what will happen very specifically in 1Thessalonians 4:15-18 “For this we say unto you by the word of the Lord, that we which are alive and remain unto the coming of the Lord shall not prevent them which are asleep. For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first: Then we which are alive and remain shall be caught up together with them in the clouds, to meet the Lord in the air: and so shall we ever be with the Lord. Wherefore comfort one another with these words.
Using Strong’s concordance we see that “Caught up” is harpazo - AV- catch up 4, take by force 3, catch away 2, pluck 2, catch 1, pull 1; 13 Meaning - to seize, carry off by force, to snatch out or away.
It is the same word used when Philip was taken up from the eunuch by the Spirit of the Lord and taken to Azotus.
Acts 8:39 And when they were come up out of the water, the Spirit of the Lord caught away Philip, that the eunuch saw him no more: and he went on his way rejoicing.
Having this understanding of the righteous being caught away by the spirit of the Lord at Christ’s return we come to Luke 17:34-36 “I tell you, in that night there shall be two men in one bed; the one shall be taken, and the other shall be left. Two women shall be grinding together; the one shall be taken, and the other left. Two men shall be in the field; the one shall be taken, and the other left.
From the different activities we might reasonably conclude that the people in question are in different parts of the world (v34 night; v35 morning; v36 daytime).
Luke 17:37 And they answered and said unto him, Where, Lord?
Logically this can only mean ‘where are the ones taken, taken to?’ because they know where the ones left, are left (bed; mill; field). “And he said unto them, Wheresoever the body is, thither will the eagles be gathered together.”
This is a parable – in real life when a dead body is left on the ground in the Middle East, eagles (or vultures) appear as if by magic from miles around. No one has to go and tell them, they are designed to see over great distances.
The Bible likens the people of God to eagles. Psalm 103:5 Who satisfieth thy mouth with good things; so that thy youth is renewed like the eagle‘s. Isaiah 40:31 But they that wait upon the LORD shall renew their strength; they shall mount up with wings as eagles; they shall run, and not be weary; and they shall walk, and not faint.
The fourth face of a cherub described in Ezekiel was that of an eagle. Ezekiel 1:10 As for the likeness of their faces, they four had the face of a man, and the face of a lion, on the right side: and they four had the face of an ox on the left side; they four also had the face of an eagle.
The eagle characteristic is the ability to see afar off. Hebrews 11:13 These all died in faith, not having received the promises, but having seen them afar off, and were persuaded of them, and embraced them, and confessed that they were strangers and pilgrims on the earth.
Not that the above is necessary to explain the parable but simply to show that eagles are not always used in a negative way. The interpretation of the parable is that the people taken are gathered to one place in the same way that eagles from all points of the compass gather to a body. By implication the ones taken are those that are alive and remain who are taken to meet the Lord.
There seems to me no reason to doubt that at the return of Christ the just will be taken to meet him exactly as described. One shall be taken and the other left behind, literally, at Christ’s return. Men and women from all over the world will be taken to meet Christ when he comes to establish his kingdom.
I hope this helps,