Ranked in these QuestionsQuestion Ranking
Pro Uses static methods
Since Flight uses static methods, it does not require for the application class to be instantiated.
Pro Open source
Flight is open source and is released under the MIT license.
A unique feature of Flight is something that the author calls filters. Filters are functions which can be executed before and after any other function and can change the parameters and the output of said function.
This feature is used instead of hooks which in other frameworks are used to execute code into different parts of the application's life-cycle.
Con Cannot use ArrayAccess
The fact that it uses static methods means that it's impossible for Flight to make use of ArrayAccess, which in turns means that it cannot inject dependencies easily.