Largest aircraft flown under a bridge

The largest aircraft known to have been flown under a bridge is an RB-47E "Stratojet" – the reconnaissance variant of the B-47 nuclear-capable bomber – which weighed 93,757 kg (206,700 lb), was 32.64 m (107 ft 1 in) long and had a wingspan of 35.36 m (116 ft). On 24 April 1959, Captain John S. Lappo of the US Air Force's 352nd Bombardment Squadron flew one of these through the 47-m-high (155-ft) gap under the Mackinac Bridge in Michigan, USA, at a speed of 724 km/h (450 mph).

The RB-47E was a six-engined subsonic aircraft about the size of a modern Airbus A320 (though significantly heavier). It had an operational crew of six (the pilot, co-pilot and navigator, plus three reconnaissance equipment operators) but only the cockpit crew were onboard for Lappo's flight.

As Capt Lappo would later describe it, the record-breaking stunt was a spur-of-the-moment impulse. He was returning from a routine training mission over the Great Lakes when the newly opened Mackinac Bridge (then one of the longest suspension bridges in the world) caught his eye. He said, "I'm going under" to his crew and dived to an altitude of around 25 m (80 ft). The plane shot through the narrow gap beneath the bridge deck and then Lappo pulled it up into a steep climb.

While his co-pilot was up for the stunt, his other crewmate was less enthusiastic. Lappo later said, "the navigator recommended against it," adding, "I had no idea at the time that he was the general's son and that he was going to go rat on me once we got back."

Lappo was immediately grounded, and four months later a military tribunal decided to fine him and permanently strip him of his flight clearance. His exemplary service record (he was a decorated veteran of the Korean War and had flown several extremely dangerous reconnaissance missions over Soviet airspace) saved him from being kicked out of the Air Force altogether.

Though he never got his pilot wings back, Lappo remained in the USAF until 1972. He served as the commander of ground crew operations at several air bases during the Vietnam War and retired at the rank of Lieutenant Colonel. Lappo settled in Alaska after leaving the air force and became a social worker.

Years later, when asked if he regretted his actions, he only said that he regretted never having had a chance to fly under the Golden Gate Bridge. He died at the age of 83 on 15 November 2003.