nothing in the inventory will tell you if the ship or vehicle or what ever is under a shield or not under one it is one of the great mysteries of the combine galaxy weather or not you can access something you own.
There is a list (or there was anyway) in the Traders Lounge that lists a number of planets that are shielded or partially shielded. I'm not sure how up-to-date it is, but at least gives an indication of which planets are already shielded as not many people unshield planets.
Originally curated by Maha Michi. Last Edited By: Maha Michi on Year 16 Day 296 23:14 so it's probably kept up-to-date.
Grisu's got a good point about making an educated guess. If it doesn't appear on the Known Shielded Planets list, and it's on the city/surface, you can also make an educated guess based on the City layout on the planet and/or the Owner of the Planet. Owner = GE or some other large faction. Probably shielded. City Layout in a Grid or FULL, probably shielded.
You can always DM the owner of the City and the Owner of the Planet to ask about shielding if it's not on the List of Known Shielded Planets. And Worst-case-Scenario, you can fly there in a fast ship and look for the blue covering when descending from Orbit.