Few things seem less likely than extended human-powered flight, but it has been done. The Icarus Cup is an ongoing competition for human powered flight. Below is a video of Zak Moore’s 1km flight in the 2018 Icarus Cup.
If you think that’s cool, consider this: The world distance record for human powered flight has stood since 1988 at 115.11 km. That’s an amazing 71.52 miles.
Kanellos Kanellopoulos (Greece) pedalled his Daedalus 88 aircraft 115.11 km (71.52 miles) from Heraklion, Crete, to the Greek island of Santorini on 23 April 1988. His epic flight lasted 3 hr 54 min 59 sec before an offshore gust broke off the plane’s tail and it crashed into the sea a few feet from the shore. – GuinnessWorldRecords
The current distance record recognised by the FAI was achieved on 23 April 1988 from Iraklion on Crete to Santorini in the MIT Daedalus 88 piloted by Kanellos Kanellopoulos: a straight distance of 115.11 km (71.53 mi). – Wikipedia
Kanellopoulos carried a 6 hour supply of an energy replacement drink and spent four hours pedaling a million dollar human powered 68lb flying machine, setting a world record noone has yet beat in 30 years. If not for a strong wind breaking the craft near the end of his flight, he could have gone even farther. It must have been an awesome experience.