The P-Wing is a special item that first appears in Super Mario Bros. 3. The "P" stands for Paratroopa or Patapata (the Japanese name for that enemy). It is a successor to the power-up simply known as the Wing.
Super Mario series
Super Mario Bros. 3
In Super Mario Bros. 3, the P-Wing allows Mario or Luigi to fly in the air with their Raccoon forms for an unlimited amount of time. However, if the brothers are hit while flying, or receive a non-flying-based power-up within a level, they will lose the power of the P-Wing. Additionally, the effects of the P-Wing only last until the level ends. After that, the brothers are left with their basic Super Leaf abilities.
If a P-Wing is used from the map screen, the letter "P" on Mario or Luigi's body (as shown in the sprite on the left) indicates that they have P-Wing abilities. The letter "P" isn't seen in the actual level or on the map screen after the level is completed.
The P-Wing can be combined with the Tanooki Suit. However, in order to do this, one must use a P-Wing upon entering a level that has a Tanooki Suit hidden within it (World 4-5, World 5-5, World 6-3, or World 7-) and collect that Tanooki Suit.
P-Wings are commonly found in chests left behind after defeating certain Hammer Bros. on the map screen. They can also be found in secret white Toad Houses (blue in the game's remakes) accessible via collecting a certain amount of coins in a certain level of a world. However, P-Wings can only be found in the white Toad Houses of odd-numbered worlds (i.e. World 1: Grass Land, World 3: Water Land, World 5: Sky Land, and World 7: Pipe Land) - the even-numbered worlds' white Toad Houses contain Anchors. Additionally, by beating the game and restarting without resetting the game, the player is rewarded with twenty-eight P-Wings in their inventory.
Super Mario 3D Land
In the Nintendo 3DS game Super Mario 3D Land, the P-Wing functions differently, warping Mario to the end of the course. If Mario touches a P-Wing, it will go into storage to use later. It only appears if Mario loses 10 lives in a level in a normal world (making P-Wing Assist Blocks appear), or within certain Mystery Boxes. However, Luigi is only able to earn the P-Wing in skipped normal world levels (for example, by use of a Warp Zone), or through Mystery Boxes. The same applies to Mario when revisiting completed levels.
New Super Mario Bros. 2
The P-Wing is seen as an icon on the P-Meter in New Super Mario Bros. 2, replacing the "P" icon in the meter's original appearance in Super Mario Bros. 3. Both the P-Meter and the P-Wing appears when Mario or Luigi gets a Super Leaf (i.e. Turns into Raccoon Mario/Fox Luigi).
New Super Mario Bros. U
Neither the P-Wing nor the P-Meter appear in New Super Mario Bros. U, but a P-Acorn (a Super Acorn with a P-Mark) appears. It is obtained from the Nabbit enemy, and it lets Mario, Luigi, Yellow Toad and Blue Toad fly for the whole level.
Mario Kart series
Mario Kart: Double Dash!!
The P-Wing makes a cameo appearance in Mario Kart: Double Dash!!. It appears on the side of some trucks in Mushroom Bridge and Mushroom City. Additionally, the license plate of the truck that has the P-Wing on it says "SMB3", a common abbreviation of Super Mario Bros. 3.
The Adventures of Super Mario Bros. 3
The only appearance of P-Wings in The Adventures of Super Mario Bros. 3 was in the episode "Up, Up, and a Koopa", where, instead of being used by Mario or Luigi, they are used by Toad and Princess Toadstool.
Names in other languages