Any air travel can be stressful, but facing down a long-haul flight can be especially intimidating.

Should you prioritize sleeping or eating, or both? Should you attempt to exercise in the aisle? Is it ever acceptable to take off your shoes?

Kris Major is a British flight attendant with 24 years’ experience. He’s worked short-haul hops and spent 14-hour stretches in the sky. He’s endured journeys with an unenviable number of layovers, and he’s become an expert in refueling via power naps at 30,000 feet.

As many of us prepare for long-haul trips over the holidays, Major tells CNN Travel his his tips and tricks on surviving multiple hours in the sky.