Air travel etiquette starts before boarding flights. Simple courtesy rules apply while waiting in the airport. An annoying offender is the obnoxious character sitting next to you yakking at full voice on the smartphone just two inches away from your ear.

Every senior traveler needs a handy smartphone to keep up with the latest. However, for the sake of everyone around you in the waiting area, when using your phone, go find a quiet corner. Then yell, squawk and scream as loud as you want.

We’re all familiar with airport delays and long waits these days and nights of inflated prices and deflated flight schedules. If you must do lay-down sleep in the terminal, don’t spread over two or more seats in the waiting area. Lay newspapers and stretch out on the floor against a wall in a quiet area.

If your schedules include frequent airport waits, always take blankets, eye shades and quick-blow-up mattresses and pillows to get as much comfort as possible. And for your own peace and quiet, try to do it without blocking foot traffic and otherwise bothering other travelers.

For common courtesy once aboard your flight, the same general rules apply. Look to your own comfort, but also be aware of the rights of others. If you’re very oversized, instead of taking up one-and-a-half economy seats, book first class.

You find the addicted smoker next to you during the flight. Clothing, hair and body still smell ... make that stink ... strongly of old tobacco. Unable to light up, the nervous, fidgeting seatmate often has a never-ending, irritating cough. If it gets too bad, ask the flight attendant to move you to another seat.

Your flight may include screaming, misbehaving, incontinent and/or barfing little ones, too often on the seat next to you. Don’t yell at the harried mother, and find ways of toning down the disruptions.

If the kids are yours, schedule red-eye (late night) flights, and with proper preparation, and after an active day, you can lull them to sleep throughout the flight. Do it for the comfort of the kids, as well as out of respect for other passengers.

Practice simple courtesy in airports and on flights. Or even more basic, follow the Golden Rule in the waiting area, as well as at 30,000 feet in the air.