Not sure if it's been addressed before but why must all climbouts be done over a spot a few kilometers from base? And why always to several thousand meters, even when the target is a balloon?

I can kind of see climbing if you're attacking a ground target that's significantly behind enemy lines. But balloons are low and always close to the front. A low altitude (just out of range of rifle fire) approach is much more sensible as it allows for less exposure and reduces the chances of not being seen by any covering aircraft circling high above the target. It also makes it easier to spot the balloon without aids.

As to the first part, climbing while enroute to your patrol area (assuming it's far enough away) makes much more sense, both from pilot fatigue and fuel usage standpoints. And for intercept missions it's critical. To be told "There are enemy aircraft inbound at X. Get up there and intercept them." and then spend 25 minutes or more climbing to altitude followed by another 25 minutes to X pretty much guarantees they'll be gone by the time you get there.

When I'm flight leader I always circle low and near the airfield until the flight is formed up and then head out, climbing as I go. And if we're attacking a balloon I'll rarely climb higher than 1,000 meters.