A few years ago my BF was preggers and I got her something by Danskin called a Pregnancy Kit or something. Basically was a skirt/pants/shirt/cardigan combo all in black knit.

http://shop.nordstrom.com/S/2929074/...bo=6005229&P=1

OK-just found this at Nordstrom. Same idea, they even have a warm weather kit. I would think they would be great fo on the airplane.

Target also has a Liz Lange maternity line.