Flew from San Diego CA to Seattle with Alaska Airlines via Portland; roundtrip reservation. Flight delayed out of Seattle; arrived on Portland for AA flight 586; told to remain in boarding area because of impending departure. All afternoon, different stories -- into the evening. Airline personnel refused to provide hotel accomodations, claiming flight would leave at any moment. When a plane did arrive, they said they had no pilot and could not fly. In the morning, instructed all passengers that they would have to fly back to Seattle to get a flight to San Diego -- that the airline had none they could take from Portland. Promised that they would arrive in Seattle and board a plane for San Diego by 9 a.m. Flew to Seattle; once there told that the 9 a.m. flight was delayed by mechanical problems; would take off at 11:30; at 11:30 told they could not find a pilot. Asked them to book passage on another airline since they could not fulfill transport -- they refused, saying their policy is not to book on other airlines as long as they have any possible planes within 24 hours. Had us all board plane; wait there and then had us all leave saying mechanical problems persisted. Spent night in chair in lounge as they refused hotel accomodations. Wearing same clothes without a shower for two days. No food as personnel would not allow passengers out of gate area. Towards midnight gate personnel did provide hotel rooms for some passengers; apparently ran out of budget money or rooms as they stopped with people still waiting and from then on said they did not have to do so as delays were not the fault of the airline. I am missing work today, stranded in Seattle. Mediation conference scheduled so financial consequences of not being at my office may be significant.