What is the highest a plane has ever flown?

Related questions

1. What is exhaust speed?
2. How much thrust does it take to lift a pound?
3. What is the effective exhaust velocity?
4. How much does rocket fuel cost?
5. Can a plane just fall out of the sky?
6. Does Eeloo have an atmosphere?
7. What is a doona in Australia?
8. What is the radius of kerbin?
9. How hot is a rocket exhaust?
10. What happens if a plane flies too high?

Tags

1. #however
2. #record
3. #limits
4. #exceed
5. #altitude
6. #aircraft
7. #absolute
8. #airplane
9. #military
10. #classified
11. #speed
12. #really
13. #blackbird