From the Steam Store page:
Air Forte is a high-altitude game of math, vocabulary, and geography. Compete with friends or fly solo in the various arenas. Good luck, pilot!
Play with friends: Up to four people can play Air Forte together. Find out who's the best pilot!
Stage variety: Play through multiple stages that explore math, vocabulary, and geography.
Unlockable game modes: Once you complete the Adventure, try the "Challenge" and "Infinite" game modes.
Online high scores: Compete against people around the world. Can you beat their scores?
Gripping story: Embark on a royal quest. Can you unravel the mystery?
In Air Forte you play a kitten flying an aircraft. In the computer versions the plane is steered by left-clicking where you want to go with the mouse. The aim of the game is to steer the aircraft into floating words or numbers that match a specific criteria, while avoiding ones that dont. For example the criteria might be "multiples of 4", and the player needs to fly into all the numbers such as "8" or "16" while avoiding numbers like "3". The vocabulary section might have a criteria such as "Verbs" and the Geography section might list a continent and ask the player to identify countries (by name and flag) from that continent.