If your condition causes sensitivity to noise, and stimulation, and/or is worsened by dealing with the unknown, you may want to consider taking a small trip to the airport prior to your flight departure to familiarize yourself with the environment and where you need to go. Familiarize yourself with quiet rest places that may help you if you become stressed or anxious in the new and busy environment and need some time between flights to get away from the stimulation. However, you will not be allowed past the security screening area and, due to security concerns, pre-boarding of the aircraft is not permitted outside the date/time of departure.
Use noise-cancelling headphones or soothing music on your flight. You should be aware that if you are boarding the aircraft at a ground loading airport where you are required to walk on the tarmac/ramp, that headphones are not permitted and absolutely no exceptions can or will be granted to allow headphones to be worn on the ramp.
Pack your favorite snacks and have them accessible to you in the cabin to act as a distraction if you are prone to being agitated or anxious. Food items, like all items, must meet restrictions for security screening. You can find more information on the Canadian Air Transport Security Authority website at: https://www.catsa.gc.ca/liquids-food-personal-items. Please keep in mind that in rare cases, if you are bringing a snack with peanuts or nuts of another sort, you may be asked to refrain from consuming them if there is a guest with a peanut/nut allergy nearby.
If you have boarded the flight but it has not yet departed and you feel extremely unwell and that travel is not going to be an option, please advise a cabin crew member. We strongly suggest that if this is a concern that you consider purchasing trip cancellation/travel insurance or check whether the credit card you will use to purchase your flight offers this as a benefit. If you have or plan to purchase insurance, please review the terms and conditions of the coverage carefully to ensure that you will have the required protection for this event. Be sure to familiarize yourself with the cancellation fees for your flight.