On Tuesday, August 22, 2017 at 3:01:06 PM UTC-4, micky wrote:
OT Very, how do you buy airplane tickets when you are going together
only one direction?

A friend and I are going on a trip together, but I'm staying longer than
she is. IIRC, when you buy tickets for 2 people online, it offers you
only the same return flight, no way to pick different ones.

Is my recollection faulty?

If you buy the tickets separately, you won't be sitting together on the
part you do together.

What to do?

You can call the airline to do the booking. Or you can buy the tickets
separately but one right after the other, view the seat reservation maps,
find the two seats you want, you take one, other person buys their ticket
takes the second one right after you do. If something goes wrong with
that, call the airline and they will fix it, assuming there are enough
empty seats to work with.