I was looking trying to find my pictures to confirm the maximum altitude I have seen on a 777 and I have a lot of shots of them doing 39,000 feet. I am sure I have seen the planes go higher, but can't find shots of it. Also, on a Southwest 737-700 the pilot stated that we were flying at 40,000 feet. The performance of the 777s is simply amazing on some east bound runs where they will hit 700 mph and you can't even tell the plane is going that fast.