Delta Air Lines

(DAL) - Get Report

Wednesday said its regional carrier Comair returned to a normal operating schedule today.

Comair resumed operations on a limited basis Sunday after a holiday weekend debacle, which has triggered an investigation by the U.S. Transportation Department. The carrier normally operates 1,160 flights a day, serving 119 cities.

Comair canceled all flights Saturday after severe weather stressed its infrastructure and its computer system for flight-crew scheduling crashed.

The federal government is also looking into massive flight cancellations and disrupted passenger baggage service at

US Airways

(UAIRQ)

.

Delta shares were down 7 cents to $7.48.