American Airlines has extended its flight cancellations due to the grounding of Boeing's 737 Max aircraft, through June 5, the airline announced Sunday. The cancellations will impact about 90 flights each day.

Philadelphia International Airport is one of American's largest hubs, with some 2,500 scheduled takeoffs weekly, according to flightsfrom.com, a travel data aggregator. The question of which flights will be affected, and how many in Philadelphia, remains a day-to-day issue for travelers.

Flight tracker flightaware.com showed 10 American Airlines cancelled flights on Monday, none of them from Philadelphia. The flight tracking site showed zero cancellations for Tuesday or Wednesday. Travelers face uncertainty as to their flight status as airlines that have significant numbers of the troubled aircraft in their fleet--including American, Southwest Airlines and United Airlines--shuffle flights at the last minute to minimize the impact of the emergency order grounding the ariline, issued by the Federal Aviation Administration on March 13. American has noted in a press release that cancelations will sometimes affect travelers not originally scheduled to fly on the 737 Max, as it re-routes other aircraft to cover gaps left by the 737 Max-related cancellations.

American "continues to await information from the Federal Aviation Administration (FAA), Department of Transportation (DOT), National Transportation Safety Board (NTSB), other regulatory authorities and Boeing that would permit the 24 Boeing 737 MAX aircraft in our fleet to resume flying," the Fort Worth, Texas-based air carrier said in a statement.

The 737 Max emergency grounding took place after two fatal crashes that involved an automated on-board system designed to push down the plane's nose, preventing it from rising too high and causing a stall.