I understand your apprehension; though I love traveling, I can never completely relax when loved ones or I am flying. I usually take one motion sickness pill, which also makes me drowsy and relaxed, and allows me to even occasionally doze off for a few minutes (my husband sleeps for HOURS on long flights!)
I find that asking my guardian angel to call in reinforcements makes me feel considerably better; my dear late mother told me that she always asked extra angels to be with us when we took long car trips to visit, or when we flew. I’ve always done the same thing, and have already asked the same for you. As others have mentioned, saying prayers, such as the Rosary, is helpful, as well.
God bless, and have a safe flight.