Sorry Mr Red. Can't agree with you on this one.
Your premise requires a much longer description. The Wright Brothers are credited with the first manned, powered flight of a 'heavier than air' craft.
The Stringfellow flight was not manned, so not the same concept.

And . . .
If you don't include the 'heavier than air' restriction then the Montgolfiers were successful in an earlier century: Montgolfier