American Airlines Flight 718, the first commercial US Boeing 737 MAX flight since regulators lifted a 20-month lockdown in November, will depart Miami, Florida, USA on December 29, 2020.

Marco Bello | Reuters

American Airlines said Monday that it may need to add stops to certain flights due to delays in fuel delivery at some small and medium-sized airports, and urged pilots to save fuel if possible, the latest headache during a surge in summer travel.

The airline said airlines, including American, experienced the delays due to a lack of truck drivers, trucks and fuel supplies.

American Airlines’ delivery delays at jet fuel stations initially mostly affected western US cities, but are now being reported at American stations across the country in a memo that has been verified by CNBC.

The airline said flights will carry additional fuel to airports affected by congestion, a process known as tankering, or add refueling stops.

“As our country continues to face numerous challenges, we should work together as a team to work reliably, safely and as efficiently as possible,” Dudley wrote. He urged pilots to use fuel-efficient strategies such as taxiing with a single engine.

American said flight disruptions due to fuel shortages have been “minimal” and no flights have been canceled as a result.

“Our team continues to work around the clock to monitor the situation and minimize the impact on our customers,” said the airline on Monday.

A Delta Air Lines spokesman said the airline had encountered some problems with fuel delays at some of the smaller western airports, but it had not experienced any operational issues. Southwest Airlines also had no disruptions due to fuel issues but could switch to tankers if necessary, a spokesman said.

“We have been and continue to be in contact with federal agencies and pipeline operators to address this fuel capacity issue,” said Airlines for America, which represents most of the major US airlines.

Captains have the power to decide how much fuel is on an aircraft.

“We want to make sure that the safety margin is protected and that we don’t leave any passengers behind,” said Dennis Tajer, spokesman for the Allied Pilots Association, which represents the approximately 15,000 US pilots.

The fuel supply issues arose during a surge in domestic vacation travel demand that was close to or above 2019 levels, according to US airline executives.

Many international travel destinations require negative Covid-19 test results or proof of vaccination for entry or are completely closed to visitors. This has increased the demand for US travel this summer, especially flights to smaller airports near outdoor tourist attractions.

On Saturday, Nevada’s Governor Steve Sisolak and several lawmakers said they were working to “triage” potential fuel shortages at Reno-Tahoe International Airport.

Bozeman Yellowstone International Airport in Montana was about half a day late on fuel deliveries earlier this month, disrupting less than a fifth of daily flights, an airport spokesman said.

More than 223,000 passengers boarded or disembarked at Bozeman Airport last month, a record and, according to airport data, more than 35% more than in the same month in 2019.

Air travelers also faced hours of waiting for airline customer service and long lines in airport restaurants and other vendors due to staff shortages.

Airlines urged their employees to take vacations or takeovers during the pandemic last year to cut labor costs, but travel demand recovered faster than many of the airline’s executives expected, and airlines are making efforts to recruit and to train.