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.
Note 10 at Lu 17:37: The disciples' question was, "Where will the ones who are taken go?" Jesus answered them in parable form, which still leaves the answer open for questions.
There are two schools of thought on what Jesus' answer means. (1) The body spoken of is referring to the slain at the battle of Armageddon (Re 16:16), with the eagles being the fowls spoken of in Re 19:17-19. (2) "Body" is referring to the body of Christ (Eph 1:22-23, 5:29-30; and Col 1:18), and the eagles are believers (Isa 40:31) who are still on the earth and will be caught up to join Christ and His body (1Th 4:15-17) at the second coming.
Mt 24:28 also uses this same example of the eagles: "For wheresoever the carcase is, there will the eagles be gathered together." This verse in Matthew begins with the word "for," which is a conjunction meaning "because." That makes Matthew's account about the eagles being gathered together tie into Jesus' teaching in the previous verse about His coming being public, as illustrated by His example of the lightning (Mt 24:27, see note 2 at Lu 17:24). Therefore, Jesus was putting away all anxiety about anyone missing His coming by saying, "Just as the eagles are drawn to a carcase, so my own will be drawn to Me." If that is the meaning of this parable in Matthew, then it is possible that the same meaning is intended here in Luke.