My mantra is that I am in charge of the drugs, the drugs are not in charge of me.
Your husband is so early post-diagnosis, that I would expect that he would be able to get around the airport in an acceptable manner after missing just one dose. Whereas, if he takes his drugs, if there's any chance of the lightheadedness causing him to faint, you might be unable to take the flight. He can have the drug ready to take, if he should need it.
Is your husband taking Requip XL (extended release) or normal Requip?
When you get back I would see the doctor about the lightheadedness. I had been put on drugs to lower my blood pressure before Requip was added to the mix. The combined effect gave me hypotension. The problem went away as soon as the blood pressure pill was removed.