The reason N2 is used in aircraft (and F1 and general cars) is the following:
1. Pure nitrogen is dry and does not absorb moisture. This helps with corrosion, but the main reason was that with air filled tyres and moisture collect at the bottom, froze in flight and created an imbalance when landing.
2. N2 molecules are larger than than O2, and so pressure loss is slower.
3. Its inert and wont contribute to a fire.