I flew w/ both kids when they were younger and we did the lanyards and boarded the plane first because they have Autism. I brought snacks just in case and foods because they were both picky but it turned out they did great. One thing I did was we traveled a few days before the school breaks to avoid crowds and came home a few days earlier.

https://www.autismspeaks.org/blog/holiday-air-t...

I only few twice both as an adult
I earned my pilot wings

Airlines offer various accommodations for passengers with autism to make air travel more comfortable and less stressful. These accommodations include pre-boarding, assistance with navigating the airport, and designated seating options like bulkhead or window seats. Passengers can also request special service codes (like DPNA) to alert the airline to their needs.
Specific Accommodations:
Pre-boarding:
Airlines often allow passengers with autism to board early, which can reduce anxiety associated with crowds and waiting.
Designated Seating:
Bulkhead seats (often with extra legroom) or window seats can be beneficial for individuals with autism, providing a sense of control and minimizing interaction with other passengers.
TSA Cares Program:
TSA offers assistance at security checkpoints for individuals with disabilities, including those with autism.
Airport Assistance:
Many airports have customer assistance desks, quiet rooms, and sensory-friendly spaces.
Special Service Codes:
The DPNA code (Disabled Passenger with Intellectual or Developmental Disability Needing Assistance) can be requested when booking flights to alert the airline of the need for support.
Sunflower Lanyards:
Airports like those in the Port Authority of NY/NJ (Newark, LaGuardia, and JFK) participate in the Hidden Disabilities Sunflower program, offering lanyards to discreetly indicate a hidden disability.
Tips for Planning:
Contact the airline in advance:
Inform the airline about your specific needs and request any necessary accommodations.
Practice at the airport:
Some airports offer practice runs for families with autistic children to familiarize themselves with the airport environment.
Pack familiar items:
Bring comfort items like noise-canceling headphones, weighted blankets, or preferred snacks to help manage sensory sensitivitie

I have. His occupational therapist gave us some social stories about planes, we made a calendar and counted down the days until our trip. I brought some toys, iPad, headphones, snacks. Anything that made him comfortable. Plus, autistic kids get priority boarding so he didn’t get overwhelmed with all those people..
It was a successful first flight.

YouTube has loads of videos on dealing with Autism and flying.

It’s said that the bulkhead is the quietest part of the plane. Try booking seats there.

Apply for TSA “Pre,” “Clear” and “Global Entry.” They will make going through security very fast with little to no trouble!

Also, apply for the Sunflower lanyard. Many airports around the world recognize this as a sign that one may need special help in the airport and getting on the plane.

And, arrange to board the plane early. This will give more time and more room to settle in.

Make sure you have a drink with a straw to equalize the ear pressure. A child may not be able to explain if they have ear pain or pressure. If he/she can chew gum, that would help but for sure drinking through a straw. If all you can get is water before the flight and your child doesn't like water, then take some flavor drops to add something appealing.