LOS ANGELES -- Alaska Airlines reports another problem with one of its jets.

The MD-80 had just taken off from California?s Ontario International Airport en route to Seattle Wednesday morning when it had to make an unscheduled landing at nearby Los Angeles International.

An airline official says the jet landed minutes after the crew noticed a cabin pressurization problem. Nobody was hurt and the 121 passengers were put on other flights to Seattle.

It?s the second time in two days that an Alaska Airline flight had to be diverted because of pressurization problems. Tuesday, the cabin oxygen masks dropped 15 minutes into a flight to Denver, forcing the plane to return to Portland, Oregon.

Alaska Airlines says three similar problem in the last two months all appear to be unrelated.