The lavs in First will be cleaner than elsewhere in the plane. Perhaps look at Kellymom or La Leche for pumping when traveling tips. I had to dump because I worked transatlantics and then had to catch another flight to home, sometimes having to go out of another airport... Just couldn't manage it.

I did tie up the lavs for awhile but it was never a problem. I did tell my coworkers, who were cool about it (even the one who moo'ed outside the lav door but let's leave that story for now!) I was more worried that they were worried that I was engaging in substances of some kind (disappearing in the lav with a bag and gone for awhile?) but you don't have to worry about the FAA drug testing you on arrival, like we did.

Lots of F/A's breastfeed and are sympathetic. The Mooing guy was an exception, and wouldn't have dared done that to a paying passenger, I assure you!

It really wasn't too bad. As long as you have a decent pump, it should be okay. If you can manage to save your milk, bravo. If not, don't worry about it.

P.S. extra tip: if the flight is over 5 or 6 hours, bring an extra bra. Sometimes a few milkdrops can escape and I need not tell you want happens to milk when it just sits there on your undergarments!