An Alaska Airlines jetliner blew out a window and a portion of its fuselage shortly after takeoff three miles above Oregon, creating a gaping hole that sucked clothing off a child and forced the pilots to make an emergency landing as its 174 passengers and six crew members donned oxygen masks. No one was seriously hurt as the depressurized plane returned safely Friday night to Portland International Airport about 20 minutes after it had departed, but the airline grounded its 65 Boeing 737-9 aircraft until they can be inspected. The National Transportation Safety Board said Saturday it will also investigate.