Ha! are you planning on wearing your suit at some time other than the interview itself? The thought did cross my mind during lunch at my last interview, "what if I dropped this piece of tomato on my tie?" Just change into your suit right before the interview and be careful at lunch and you should have no problems. On a related note, I didn't realize some (most?) airlines have wardrobe lockers that you can use free of charge, maybe give the airline a call and see if yours does.