I'm the one who gave this suggestion. In adition to the quotes posted i would like to add that most of us could make a spreadsheet in excel and input the maint values for each plane, put limits and control the ones we tough are higher but that would take a lot of time to the game and would make it boring.
If this feature is incorporated in a simple way to the view page aircraft we are able to make the same control ingame focusing on higher maint values (usually planes with a lot of quicker routes).