Originally Posted by GUWonder

Here is my general order of preference in seeking ticketing of lap children:

1. Online at time of booking.
2. Over the phone at the time of booking.
3. Over the phone some time between booking adult ticket but before going to the airport.
4. At airport days, weeks or months before date of travel.
5. At airport day before date of travel.
6. At airport several hours before time of travel.
7. At airport 3-4 hours before time of travel.

Despite my preference, it’s often ended up being 4-7 when the adults are flying on award tickets and has worked out fine.

No matter how it’s done, watch out for a lap child ticket number and get the ticket receipt details/printouts to make sure things are done right with the lap child ticket and flight booking info so as to match at least the flight segments details for the accompanying adult being flown with the lap child.

Airlines too often mess this stuff up in small or big ways when not having done the lap child ticketing online at the time of adult ticket booking on regular paid ticket. And with airline mess-ups it can turn into work at or while at the airport. And in conjunction with adult award tickets, airlines are even more likely to mess this stuff up.

The point is that lap child ticketing is often possible while at the airports or ends up required to be done/redone properly at the airport; and doing it at the airport should be considered when told no over the phone or given questionably high lap child fare quotes over the phone.