In the "Pokémon" games, Dragonair evolves into Dragonite starting at level 55. The evolution does not require trading Dragonair, using evolutionary stones or increasing its friendship value.
When Dragonair evolves into Dragonite, all its base stats receive an increase. Its attack raises by 50, its HP, defense, special attack and special defense raise by 30, and its speed raises by 10. Dragonite also gains the flying-type in addition to the dragon-type, allowing it to deal stab damage with flying-type moves, learn the move Fly and gain immunity to ground-type moves.
Dratini, Dragonair and Dragonite are the only three dragon-type Pokémon introduced in Generation I. Only one more, Kingdra, is introduced in Generation II.