I flew with DD at 5, 6 and 16 weeks.

I wrapped her and fed on takeoff and landing (she's a wrap gangsta) and she slept a bit. At 16 weeks she was going through a bit of a phase of breast refusal, so I packed two dummies, which she doesn't normally use.

We caught public transport to the airport with her in the sling, she's always happy in there. We also packed a mat that we could spread her out on for a kick around while we waited to board. That helped with cabin fever when on board.

Otherwise, just packed nappies, spew cloths, the usual nappy bag stuff.