DALLAS—As Spirit Airlines marks a third month in its repeat restructuring, industry entrepreneur and airline founder David Neeleman is weighing in on Spirit’s chances of survival.

David Ellison soloed on his 16th birthday and began competing in airshows at 17. In 2003, at 20, he became the youngest member of the Stars of Tomorrow aerobatic team at the EAA AirVenture Show in Oshkosh, Wisconsin. He flew a Cap 232 painted in full Flyboys regalia to promote the 2006 film.