colored diagonal lines are what?

[Treefrog]

Occasionally a hex behind my front line will get diagonal colored lines and the unit therein is prevented from full range of action (reinforcement is common).
What is this about?

[Hubert Cater]

What color are the lines you are seeing/referring to, green or orange?

[Treefrog]

red, sometimes purple.

[BillRunacre]

If they are appearing under aircraft units then this will reflect that they are either not supplied by a HQ (red) or could gain better supply if attached to a different HQ (purple).

[Treefrog]

thanx for the answer; as I recall they were air units. good to know