That is an amazing record. I had not heard this one before. A testament to American Ingenuity and Craftsmanship.
One more for the books- the B-36 was responsible for determing the maximum altitude that birds could fly. In 1954 a B-36 flying SE out of Thule, encountered a flight of 30 Trumpeter Swans flying at an altitude of 27,000 ft. The existing altitude record for any species of bird