The Bathroom or a Glass of Wine

Flying coach on the plane home from Europe last weekend, I had to have a glass of wine; so I paid $6 and was hit by the airlines’ revenue-increasing, pay-by-the-piece policy. I asked a flight attendant when the airline would start charging for use of the toilet and got a laugh, but no answer.
USA Today had a poll asking people, “Would you fly on airlines that charge for access to the restroom?” Most respondents said no, but I bet that people wouldn’t let this bother them, they wouldn’t alter their flight plans, and they would pay for use of the toilet.
Pricing the bathroom would reduce the quantity demanded; some people would wait and race off the plane to the airport bathrooms (unless airports started charging also). But I would think that the demand for using a plane’s bathrooms is fairly inelastic, so that — except on short flights — behavior wouldn’t change very much.
Of course, if airlines started charging for bathroom use, it would affect their sales of drinks, since drinks and bathroom use are complements. So perhaps charging for bathroom use is not a good idea; airlines’ revenues might even drop!