Upvote:1
It is possible on most airlines to "link" two separate reservations that have already been made. This effectively attaches a note to the two separately-booked itineraries saying in effect "these two people are traveling together, please seat them together and don't re-route them onto two separate flights if the original flight is cancelled." In general, you will need to call the airline's customer service line to link two reservations in this way.
That said, it is not clear to me (from reading accounts online) how often these "links" are respected, particularly by automated rebooking systems. It can't hurt to link the reservations, at least, but you may still need to be diligent about seat selection and/or rebookings.
Upvote:2
Within the US, there isn't round-trip pricing any more on most airlines; the price of a round trip is just the sum of the two one-ways. So you should buy:
If this isn't a US domestic flight, I'm not sure if there's round-trip pricing, but you can easily get prices for tickets and see if there is or not.
The advantage of doing it this way (as opposed to buying a round-trip for you and a one-way for your daughter) is that if something goes wrong on the second leg the airline will make efforts to keep the two of you on the same plane.
(As it turns out I just got back from a trip within the US exactly like this, and I booked it in the way I described.)
Upvote:3
I don't know which country you are in or which airline you intend to use, but many airlines will allow you to select the seat number during the online booking process. Most of the so-called low-cost airlines charge an extra fee for seat selection.