Weather news
A 747 hit 726 mph over the Pacific Monday morning, and it's not supersonic
By Ryan Hall, Y'all Weather Desk · Published
Written by our automated news desk from National Weather Service data.
Key points
- Ground speed is not air speed. Flight 5Y802 was flying from Shanghai to Anchorage. Its speed through the air was about 561 mph, which is Mach 0.83, a normal cruise for a 747.
- The sound barrier is about the air, not the ground. At that altitude the air is around minus 48 degrees Celsius, so sound travels about 673 mph. The plane stayed well under that.
- The jet stream did the rest. The wind at the plane's level was about 183 mph. It peaked near 216 mph a bit farther northeast. Add a tailwind that strong to the plane's own speed and the ground speed jumps.
- This is not a glitch. The number comes from the plane's own tracking signal, not an estimate. It held between 609 and 634 knots for the whole cruise since about 6:14 AM ET.
An Atlas Air 747 freighter was moving 726 mph over the ground at 8:01 AM ET Monday, about 33,000 feet up and east of northern Honshu, Japan. It did not break the sound barrier. A 183-mph jet stream was pushing it along.
Some of you asked whether a plane flying 789 mph over the ground had gone supersonic. It didn't. The same tailwind effect is why flights across the U.S. can run faster or slower depending on direction, and you can check the airport delay outlook for your own travel.
The live map and data are on our home page.
More on November 2026 weather
Places in this story: Anchorage, AK
Sources
- GFS, 06Z run, NOAA National Centers for Environmental Prediction