Angels One Five

From the introduction -

"This is a simple grand tactical simulation game of the interception of an escorted formation of multiengine daylight bombers during World War Two. Two players or teams direct the actions of the escorting and intercepting fighters as they seek to inflict losses on the opposing aircraft while minimising their own losses. In team play, each player controls one or more specific fighter units, depending on the number of players and the amount of time available."

The counters come in four different sizes, with each larger size corresponding to the next higher altitude band (hence giving an intuitive representation of height, since higher units appear closer and so larger from an overhead perspective).

One of the games in Philip Sabin's book "Simulating War", with counters and map downloadable from his website.

This game has now been published in a deluxe edition by Victory Point games, with full colour components and added historical scenarios.