How long can a hot air balloon fly continuously?

Answer 1

for as long as it has fuel to heat the air - it takes a lot of fuel to keep a large amount of air warm enough for flight which is why most hot air balloon flights dont last very long there is a technique that piper cub pilots used to do pre WW2 for long endurance flights that could work for balloons as well though i dont know if its been tried - piper cubs can fly very slow so would fly just above a car that would then hand off fuel and oil and food - the cubs were modified to be able to add fuel and oil by the pilot in flight by opening the windshield and standing half out of the aircraft - some very long endurance records were set, dont remember exactly but i remember hearing one of at least 30 days - same sort of thing could be done with balloons by using chasers to hand off fuel and supplies - but not easy as balloon direction, speed and fine control are not that great but it probably could be done for a very long time with luck