Straight line and diagonal distances in CoW are relativity important when:
1. Attempting to figure out best locations to construct AB's (as pointed out above by WayneBo).
2. Figuring out which AB to use to set up rockets to reach a specific target.
3. Figuring out defensive positions / staging of air force units once enemy air force units have been discovered (types / levels, etc.)
4. Please add any other reasons why distances are important here.
4a.
4b.
4c.
Distances over roads are relatively unimportant because the program provides the shortest distance between two points by default (for an individual unit or the slowest unit within a stack). If the chosen path is not preferred, then another path can be chosen by adding additional targets to the path, thereby increasing the travel time as well.
Coordination of travel times can be done with the utilization of the "delay arrival time" function.
Screen graphic resolutions impact each individual users visual perspective of "scale", making it practically impossible (guessing here) to establish (develop/program) "scaled" maps.
Distances over water are determined by the path chosen similar to how units are routed over land. Therefore, actual distances are much less important than the actual travel time involved.
The "ovals" which designate a particular type of plane's travel zone/range are constructed in a ratio of x" (horizontal) to "y" (vertical). As well there is a "z" (diagonal) distance associated with the oval. Each flight range therefore has a specific set of oval "ratios" (measurement / distances) which can then be utilized regardless of the plane type / level as the ratios of the oval are attributed directly to the stated flight range.
Once each of these ranges is available to you to see on your monitor, the only way I have discovered to be able to "closely estimate" the x, y and z distances of each oval is with the use of a ruler placed on the monitor screen.
But, please keep in mind that these x,y,z distances change each time the screen resolution (map size) is changed.
I've tried third-party software applications that calculate distances between two cities, but haven't convinced myself they are as accurate as simply using a ruler placed on the monitor and then transferring those distances between two points on the map.
Again (and most importantly), this oval changes sizes with each change to the monitor resolution and/or increase / decrease in map sizing.
Hopefully, there is some forum member who can provide a more technical perspective / reason(s) for why providing distances of travel (in Km / miles, etc.) is not something easily "added" to the game mechanics.
It would, however, be a great addition to the game mechanics, if there were a way to be able to utilize a "line tool" that could be scaled to the ovals described above or better yet scaled to the various flight range distances associated with the game.
Or optionally, ovals are the game tools added to the game mechanics and you just click on one to activate it and then double click to deactivate it.
ps. you can somewhat (sometimes?) see the "next oval" that will be attributed to a plane when it is going to be moved (relocated) to another AB, in the form of a "dotted oval" which can sometimes be helpful when attempting to figure out where to establish another AB. (I think this statement is correct - but not playing a game at the moment so cannot verify. Please feel free to clarify or correct this statement. I will delete or line through if incorrectly stated.