1289km/h! Virgin Atlantic passenger jet unintentionally hits speed of sound between Los Angeles and London

The Virgin Atlantic Boeing 787-9 Dreamliner appears to have broken speed records for the aircraft. Photo / Getty Images

A Boeing 787 Dreamliner from Los Angeles to London Heathrow has unintentionally returned us to the era of 'faster than sound' flight.

The Virgin Atlantic flight broke previous speed records for Dreamliners, reaching an impressive top speed of 1289 km per hour. It completed its journey in 9 hours 13 minutes.

More impressive still, the 787 service attained a top speed faster than the speed of sound.

The plane tracking FlightAware website shows the Monday service from LAX reported its top speed of 1289 between 15:22 and 15:26 flying over Pennsylvania.

An extraordinary speed considering the cruising speed of a Dreamliner is 913 km per hour and the speed of sound is just under 1235km per hour.

Although the speed dropped significantly over the Atlantic, the service was able to shave almost an hour off of the journey time.

Faster than sound: The Virgin Atlantic flight reached top speeds of 1290kmph over Pennsylvania. Photo / Flight Tracker

The flight arrived a whole 48 minutes ahead of schedule with a flight time of 9 hours and 13 minutes.

This was in part due to extremely strong tail winds.

Meteorologist and TV weatherman, Paul Deanno first drew attention to the flight while tracking the jet stream winds.

"The jet stream is so strong over the US right now... that Virgin Atlantic Flight 8 from LAX to London is whipping above Kansas at a ground speed of 758 miles an hour," he tweeted prematurely.

"That's almost the speed of sound..."

The excitement spread amongst the aviation community online as the plane pushed through the cruising records and eventually the speed of sound.

"Almost 800 mph now never ever seen this kind of tailwind in my life as a commercial pilot !! (200 mph tailwind )," responded pilot Peter James, as the plane reached faster than sound speeds.

Almost 800 mph now never ever seen this kind of tailwind in my life as a commercial pilot !! (200 mph tailwind ) pic.twitter.com/0XGTkEP9EB

— Peter James (@jetpeter1) February 19, 2019

The flight was helped along by winds sometimes exceeding 320km per hour.

While Boeing is unable to confirm if the speed reached by the Virgin Atlantic flight was a record for its Dreamliner - as it does not track aircraft speeds - the ground speed reported by the plane was a new fastest for the 787.

The previous record, set in February last year, tracked a Norwegian Dreamliner which also made the fastest Transatlantic crossing at just over five hours.

The Norwegian Air New York to London service was also helped along by the jetstream to reach 1285 km per hour.

Record time: Desipte slowing over the atlantic VIR 8 arrived a whole 48 minutes early. Photo / Flight Tracker

Both these 787 services helped along by jet stream winds exceeded the speed of sound, but they were not 'supersonic' flights.

The Dreamliners did not break the sound barrier, something not done by a passenger plane since the grounding of Concorde.

Dreamliner has a long way to match the French supersonic jet, which cruised at speeds of 2179km without a tail wind.

The Concorde still holds the record for the fastest crossing of the Atlantic in 1996, at a brisk 2 hours 52 minutes and 59 seconds.

Virgin is yet to provide comment.