 With the delivery of Boeing 737 Next Generation aircraft starting in 1999 , Alaska began launching more medium @-@ haul flights . In 2000 , Alaska started service between Anchorage and Chicago . On May 15 , 2001 , the airline took delivery of its first 737 – 900 . In 2001 , the airline was granted slot exemptions by the Department of Transportation to operate a nonstop flight from Ronald Reagan Washington National Airport to Seattle , but it was halted after only a week due to the September 11 , 2001 attacks . The airline resumed service to Reagan Airport on December 4 , 2001 to meet the demand . 
