Flying standby from Heathrow Terminal 3 is, btw, a complete fiasco. As you're not allowed to wait at the gates after the flight has closed, you have to proceed through the ordinary flight connections security checkpoint as if you'd already travelled somewhere. This means standing in a queue for upward of 40 minutes - and having to have your bag and shoes screened again! It is ridiculously frustrating to have cleared security in Heathrow Terminal 3 once and then have to go through the same thing again, long queues and all!
The really stupid thing is that there's that same restriction on liquids of more than 100ml. So, although you went past a sign that said "you may now buy liquids of any size", you appear to be expected to throw away the drinks you bought inside the departure lounge! I don't know for certain that this is the case because I was already feeling vulnerable due to the lack of chairs for people to sit on to take shoes off . I had a receipt showing I'd bought my smoothie in the departure lounge, but considering the shoe problem , I didn't want to add complications. Yes, flying standby is extremely crip-unfriendly.
 I roll my ankles very badly, so need to wear boots with sensible support. I also have orthotics. These are both incompatible with slip-on shoes. In any case, I can't easily bend over and stand on one leg at the same time.
 They brought me a stool to sit on when I asked. But it seems crazy that there isn't one there for all the elderly and disabled passengers who aren't in a bad enough state to need wheeling through the terminal yet still can't easily bend down.
When I finally get to Minneapolis, I will so need to get a nice meal and a shower. My skin and mucous membranes feel dirty and dehydrated from the horrible dry air.