Please understand I am not providing any medical advice. Ask your medical provider for advice on your specific medical needs and appropriate treatments. That being said, when I get sick before a trip....
Afrin nasal spray. DO NOT USE IT MORE THAN 3 DAYS! However, it will get you through the worst days! This dries up your nose, and makes the "beans" (turbinates) in your nose shrink, so you won't be stuffled up.
Sudafed. The real stuff, not the "new"/fake stuff. Depending on where you live, it may require a prescription, or may be behind the pharmacy counter. This acts as a general decongestant (it dries you up). This will also help you avoid extra ear pain from fluid in your ears on the plane.
Neti Pot if you can handle it. I can't. But some weird people in the world seem to love it. (TEASING! I hate it, but I know plenty of people that love it, and I met a lot of them when I was working at an ENT office!)
Pay attention to what meds you are using--its pointless to use a cough suppressant with an expectorant. That's saying, "Help me get this crap out of my lungs, but don't let me cough it up!" It's a common mistake
Remember that Tylenol and Ibuprofen are two separate medicines. So, you can take both if you aren't taking another NSAID (like Aleve, Meloxicam, and other medicines for inflammation).
If you will be on vacation at the 2-week point of being sick, consider asking your medical provider for an antibiotic to use just in case, so you aren't stuck trying to find an urgent care that takes your insurance. My care team is pretty understanding about this, and willing to do it.
Don't forget the natural remedies--warm tea with or without honey can help open you up and calms coughs, and eucalyptus helps open up snuffled nasal passages.
Oh, and HYDRATE HYDRATE HYDRATE! Not drinking water won't dry you up, but will make you feel worse!
And soft, soft tissues. Like the $$$$ ones. Just suck it up and buy the good ones. And carry them with you in the parks.
Can't tell who has gone to DL with a cold our two, can we? Hahaha.