WASHINGTON, D.C. — A comprehensive report on why a Northwest Airlines flight overshot the Minneapolis-St. Paul International Airport by 150 miles last month is expected to be completed by the end of the year, National Transportation Safety Board Chairwoman Deborah Hersman said today.

Northwest Flight 188, en route from San Diego the evening of Oct. 21, eventually turned around near Eau Claire, Wis., before landing about an hour late in the Twin Cities. The pilot and co-pilot, who were unreachable for more than an hour as the plane sped past the airport, told investigators that they were distracted while working with new scheduling software on their laptop computers. The pilots' licenses were revoked by the Federal Aviation Administration, but both men have appealed the decision.

"We believe the pilots to be truthful about working on their laptops during the incident, but the investigation is continuing," Hersman said, adding that there is a chance the investigation could stretch into January "at the latest."

Sens. Al Franken and Amy Klobuchar are among those who have called for a complete ban on pilots using laptops in flight.

"We don't tolerate texting while driving, and we're certainly not standing for it while flying," Franken said in a statement shortly after the incident. "It would be unthinkable to allow a driver to use a laptop. A driver responsible for the lives of dozens, if not hundreds, of passengers needs to be that much more focused on the job."