A British-Belgian teenager became the youngest person to fly solo around the world on Wednesday after a five-month journey that saw him battle monsoon rains, searing heat and bureaucracy.

Cheers went up as 17-year-old Mack Rutherford landed at an airfield near the Bulgarian capital Sofia after flying 54,124 km (33,631 miles) and visiting more than 30 countries since he departed from the same site in his Shark Aero microlight airplane on March 23.

"There were many points in my journey where it would have been easy to give up...But I kept going, even when it seemed like I wouldn't be able to make it to the end," he said.

His journey broke two Guinness World records, including one set by his sister Zara, 19, who handed him one of the certificates on the tarmac.

"Amazing to finally be here again and to have done my goal," he said with a wide smile. "It took a little bit longer than I had hoped for, but it was very exciting, very interesting trip and I don't regret at all going on it."

Rutherford's journey took longer than planned due to permit delays that forced him to alter his route twice and fly over Africa, the Middle East, South Asia, North America and back to Europe.

His favourite flyovers ranged from the Sahara Desert to Greenland and Iceland. But his trip was also full with challenges, like a 10-hour flight from Japan across the Pacific Ocean to the uninhabited U.S. Attu Island during bad weather.

In Sudan, his solar panel system fell down because the heat melted the glue maintaining it in place combined with extreme haze. In India, monsoon rains entered his main fuel tanks and soaked his aircraft including some documents on board.

Rutherford became the youngest person to fly around the world solo, taking the title from Travis Ludlow, who was 18 when he completed his attempt last year.

He is now also the youngest person to fly around the world in a microlight aircraft, the title held previously by sister Zara, who completed her own trip around the globe in January this year.

For now, he is not planning on breaking any new records but to go back to school and catch up with his studies.

Rutherford, who gained his pilot's licence in 2020 when he was 15 after training with his father, hopes his five-month voyage will encourage young people to pursue their dreams.

"Basically, just work hard and push forward with your dreams no matter how old you are. Just keep moving forwards and your dreams will eventually come," he said.