Terminal 5 at Heathrow has a massive wall of glass out on to the airport. However, it is not so easy to get any shots of the planes given the amount of space that is given over to retail. However, the piers from which many of the flights depart are a better proposition. Our flight was leaving from 5C so we headed over there a little ahead of time. Apparently, this might not always be a good idea if they change gates because transferring back is not as straightforward. However, we didn’t have any problems.
Head to the north end of the pier and you can sit with a pretty unrestricted view of the departing aircraft from 27R. They tend to rotate quite close to where you are so you have an excellent opportunity to watch the movements. Shooting through the glass is possible but not ideal. Internal reflections are, of course, a big issue but sometimes you can avoid them and other times you hope they are not too noticeable. Not material for publication but certainly useful for getting something that you would not normally see elsewhere.
I spent a happy half hour getting shots of departing jets prior to the time to head to our gate to board. The only disappointing thing was how many US airlines I got. I can get them at home! Our plane was actually in front of me while I was taking my pictures. It was connected to the terminal by a very long jet bridge so, when we finally boarded, we had a long walk to actually get to the jet. Not as long as the flight was of course!