as a traveling, pumping mama, i'd like to add my $0.02. besides all that has been mentioned above:
- to pump, you need at least 30min block of time. when traveling, knowing for certain you can stay put for 30 min is sometimes very difficult to plan for. i've had time while traveling that a 45min flight was the only 30-min period i had within a 2-3 hour window (between security, gate changes, boarding, delays, takeoff, landing, waiting for gate, tight connection, etc).
- pumping in lav - i've done it. some FA are very helpful and look out for you. others less so. i've had people banging on the door irate that i was hoggin the lav (esp on a small plane with 1-2 bathrooms). another issue is turbulence and seatbelt signs. as soon as it goes on, some FAs were demanding i stop and return to my seat. once you are hooked up to the pump, you can't just hit "pause".
-i've pumped in seat and i can assure you this was my absolute last choice when i couldn't come up with any other feasible option.
-pumping schedule is pretty tight. early on, you may feed every 2 hours (and that's from start to start, not from end to start), so you have 1 hr max maybe between end of one feeding to start of another. pumping has to stay on same schedule or else you may loose your supply.
-airport is not always easier to pump. most airports don't have private bathrooms/rooms. regular bathrooms usually lack electric outlets or any place to put the pump (it doesn't reach if placed on the floor and you can't keep all parts on your knees as things will fall). gate areas are usually pretty crowded and even more exposed being out in full view of multitudes of people.
i don't know any pumping mother who likes to travel and deal with pumping, but due to lack of maternity leave in the US, for some of us it's the choice between having a job or not.