Delta Air Lines says it has protected its planes against interference from 5G wireless signals

ATLANTA (AP) — Delta Air Lines says it has upgraded its entire fleet to protect the planes against radio interference from wireless signals. The airline said Thursday that it completed upgrading about 190 planes over the summer. Some aviation experts worry that interference from new 5G wireless signals could interfere with critical equipment on planes. Other big U.S. airlines met a July 1 deadline to upgrade devices called radio altimeters, which measure the height of a plane above the ground. Delta says it worked with a supplier to catch up and retrofit the rest of its 900-plane fleet.