The storm, considered the strongest since 2005, has caused minor disruptions for U.S. airlines, and Delta said it altered routes for "a handful" of flights, and that the changes were adding about 15 minutes to travel times.
"We are undergoing a series of solar bursts in the sky that are impacting the northern side of the world," Delta spokesman Anthony Black said.
"It can impact your ability to communicate," he said. "So, basically, the polar routes are being flown further south than normal."
United Airlines spokesman Mike Trevino said the carrier diverted one flight on Monday because of the storm, but none on Tuesday.
American Airlines reported no operational impact due to solar flares but that it is monitoring the atmosphere, spokesman Ed Martelle said.
The National Oceanic and Atmospheric Administration said in a press release on Monday that it had issued a watch on Sunday for "a geomagnetic storm associated with a bright flare on the sun."
NOAA said it was the strongest solar radiation storm in more than six years - and it was forecast to hit Earth's magnetic field on Tuesday, and it could affect airline routes, power grids and satellites, the U.S. Space Weather Prediction Center said. A coronal mass ejection - a big chunk of the Sun's atmosphere - was hurled toward Earth on Sunday, driving energized solar particles at about 5 million miles an hour (2,000 km per second), about five times faster than solar part
( Editing by Phil Berlowitz and Eric Walsh)