Summer is supposed to be a time for vacation and forgetting your real-world problems, but if your plans involve air travel, escaping frustration and inconvenience might be harder than you thought. This summer, it seems a perfect storm is brewing that’s poised to complicate air travel for millions of travelers, according to Bloomberg. The first issue is the potential reassignment of hundreds of airport security personnel to the Mexican border, and the second is the continued groundings of Boeing’s 737 Max planes, after fatal crashes in March of this year and October 2018.

The Department of Homeland Security (DHS) is considering transferring dozens of air marshals and 400 airport screeners from the TSA to help with border operations — a move that could both impact air safety and security, as well as cause longer airport lines. Sara Nelson, president of the Association of Flight Attendants-CWA, said, “As the busy summer travel begins, it couldn’t be a worse time [to] undermine important safety programs and endanger the safety, security, and comfort of the traveling public.”

The DHS has pledged to limit the amount of staff taken from airports already short on personnel, but airports around the country are likely to feel the impact regardless.

Perhaps a more immediate and pressing problem is the grounding of the 737 Max planes. After two fatal crashes, three of the four largest US carriers have grounded the 737 Max, putting a strain on their fleet capacity. American Airlines Group Inc., Southwest Airlines Co., and United Continental Holdings Inc. have all removed the model from their schedules through August — typically the busiest travel period — leaving the rest of their fleet to pick up the slack. The grounding has caused United to cancel 2,410 flights in June and July, with American saying that the groundings are causing 115 daily flight cancellations.

So regardless of where you’re planning to travel this summer, don’t be surprised if your vacation hits a snag or two, and make sure to arrive at the airport early.

H/T: Bloomberg