It will affect the P4, as soon as you enter the defined DJI No Fly Zone around the airport, if any! The app will land the aircraft in place! While it is landing, you may have time to turn around and fly out of the NFZ, which will then cancel the Autoland! You will also get a warning that you are approaching a NFZ before you actually enter it, which tells you to fly safely, and must be acknowledged. Big Brother is watching and in control! This also apples to any DJI enabled NFZ's surrounding Stadiums, even if empty! The NFZ's should appear in red on the map in the app during flight, too. The NFZ is about 6 blocks away on every side of a Stadium. Ask me how I know!
As stated above - if the airport has an associated no-fly-zone then while it will not affect the radio link it will prevent the Phantom from entering the airspace. If the airport and vicinity is not defined as an NFZ in the Phantom firmware then there is not likely to be anything that directly affects it. Radar (if present) operates on a quite different frequency band and there should be no other EM emissions from the airport that cause problems.