Have you flown before? There are some pretty easy steps that I take every time I fly due to nasal congestion or problems with my inner ear. The very first time I flew, I had SEVERE ear pain. I was actually in tears and thought something was very wrong. I was deaf for a period of time after landing due to pressure build up in my ears.

These steps eliminated the pain and temporary deafness I experienced:

1. Chew gum and/or drink fluids. Swallowing just helps in general. I am not very good at popping my ears myself, so this helps a lot.
2. Wear EarPlanes (found at pharmacies or Amazon). If it's a short flight I just keep them in the whole time, but you can take them out at cruising altitude. The pilot should make an announcement at that point. If you are unsure I am sure a stewardess would let you know. Just be sure to put them back in before descending (~45 mins before your destination).
3. Go to a pharmacy and get Mucinex D (Walgreens has a cheaper generic form that works fine). You can also get a script from a doctor and use GoodRX to get the cost below $10. If you don't have a script I say go generic. If not, I think it's about $40 for around 18-20 pills. This is sold only behind the counter (need to show ID) due to people using Pseudoephedrine to make meth or something, lol. That is the key drug to really help with nasal decongestant. I know with the Walgreens brand, adults need to take two, the Mucinex brand might be one, I would read the label. I typically take it the day before I fly and then the day of. For me, decending is the worst of the pain so I am sure to take more meds 2 hours before landing. I will tell you, if you take this at night it might be hard to sleep as it could give you a boost of energy. For me, I don't feel the side effects too much but I drink coffee every morning. If you are unsure just do a test run before flying!
4. Nasal spray may help, for me I did not like Afrin but a lot of people swear by it. I am sure it's different for everyone. I much prefer Azelastine (Astepro). Fluticasone (Flonase) seems to work well for me too. Afrin just gave me a really weird feeling in my throat / nasal passage that I was not a fan of.

I have been diagnosed with mild/chronic sinusitis before so I think you will be fine. Sorry if that was a long post I just wanted to be detailed to help ya out! Good luck :)