The Players are the main protagonists of the Airplane series and the Starblox series. They make an appearance throughout the Airplane saga, as well as spin-off games and other games made by Ponchokings.
In Airplane 1, 2, and 3, "The Players" refers to the same group of people. We know this due to the fact that Ronald remembers us and blames us for his death when, other than the captured noobs, the only people on the plane were the Airplane 3 players and General Poncho. The players in these games are evidently military personnel, which is inferred when they are chosen by General Poncho.
Airplane 4 Protagonists
There is plenty of evidence that the players in Airplane 4 are different characters than in the prequels. For example, the Good Ending of Airplane 4 reveals Pilot Keilly to be the mother of the players. However, Pilot Keilly was a child in Airplane 3, when the players were old enough to be in the army.
The Protagonists of Castle are separate from the Airplane Saga Protagonists as they used to work with Diana to escape her castle and confront the dragon at endgame. However, due to them living a long time ago is what gives proof that they are not the same protagonists.
Starblox Stories Protagonists
The Starblox Stories protagonists are different from those that appear in the Airplane series. They are soldiers working for the Great Constitution, underneath the command of Hunter.
Pet Story Protagonists
Also See: Pets
Pet Story protagonists are a group of pets that were adopted by Grannie with Canela. As the story progresses, they have to confront the main problem in one of the four endings within the game to help out or save someone from something.
Hello Penguin, Super Size Obby, Age Simulator, & Platform Madness Protagonists
Although the players star in this game, they aren't technically counted as protagonists due to the game not being a story game unlike the ones listed above and that the games are a different game type of game.