My question is, Can i purchase a round trip flight to fly and pick up another person and return on the same flight with that person? I have children that aren't able to fly alone. My plan is to buy a round trip for all of us but i'll be flying to pick them up at the airport and have them return with me. im not sure if thats possible to do.
No, you cannot be on the same reservation as your children if you intend to fly out and return (AAA-BBB-AAA), but they will only accompany you on the return (BBB-AAA).
If a passenger misses any segment of a flight itinerary, all subsequent segments are forfeit. Since your children did not fly AAA-BBB, they would not be allowed to fly BBB-AAA. The reservation system will have canceled the tickets automatically.
You can, of course, purchase separate tickets, a round-trip AAA-BBB-AAA for yourself, and a one-way BBB-AAA for the children. You can further call the airline and ask that the two records be linked, so that if there are complications with either, the airline agent knows to check both reservations. This will also entail a little more effort for coordinating seats and boarding groups as well.
Sure, this has been done. It's not anything really special.
You book at round trip, say LHR-LAX-LHR. You book the kids a one-way on the same LAX-LHR flight as you.
Depending on the airline, you may be able to link the reservations so any Agent who assists you will see you are traveling with other passengers.
Also, presuming you want to sit with the kids, you may, depending on the ticket class and your status with that airline, have to pay a fee to select seats together.
Basically, there's nothing stopping you from doing this, it just take a bit more coordination.