Quite often at Luton you can see a flight at the distant end of Rwy26 with an inbound aircraft visible on the approach. It all works out generally well but, when I was there recently a departing Wizz Air flight had been cleared to go but didn't move immediately. Meanwhile a Ryanair flight was getting closer and closer. Eventually, it was so close I began to wonder what would happen now. As I was thinking that, it all happened at once. The Ryanair flight changed his mind and began a missed appraoch. At the time, Planefinder was showing this one at 350ft. As he began the procedure, he was directly above the Wizz Air flight which decided it was time to go so there were 2 aircraft travelling in the same direction. 1 on the ground giving it max revs and another directly above him a couple of hundred ft above. Within a couple of seconds, the Wizz Air flight made a heck of a noise with the noisiest brakes I have ever heard. The Wiazz Air then trundled sedately to the 2nd junction, turned off and set off along the taxiway to join the back of the queue. Almost nonchalant! I wasn't listening to the radio but I bet there some stern words!