They had ground observers, observers on ships, some radar, and inflight observers that would give basically the same information we get, that aircraft are in a given area.
Some valid points I hadn't considered...

I do agree that a small tweek may be in order, however. I just have a hard time understanding, especially on larger maps with more distance between "front lines" and the relatively safe rear (HQ & Strategic Factories), why the enemy countries have the ability to see a radar bar as deep into enemy territory as we see in the MA. I can watch a large strat raid coming for 40 minutes... Granted that allows time for a defensive, but it seems somewhat unfair to the buff pilot to immediately indicate to the other two teams that a climb out is occurring.
Personally, as per the drawing posted above, I would like to see a two tiered radar system in place which only extends a certain distance beyond the "front line" bases. The first tier indicates lower-level aircraft (200ft - 25k ft), and a second further reaching high altitude radar indicator (25k-Space). This would still allow a country to have an understanding of the enemy aircraft's intent as they enter friendly airspace, high alt dar bar flashing, seems to be buffs carrying through to targets deep in friendly territory.... Dar bar is standard and huge, looks like our front line base(s) are under attack, SCRAMBLE!
The only part I'm having trouble explaining is the implementation.... Do we have two distinct dar bars indicating high or low alt contacts? Also I'm not sure what would be an acceptable range fro the low and high alt dars to extend.... I'm assuming that these distances would be a function of the map size, as well as, distance between initial front line bases.
