How a balloon lands, and why there is champagne
You cannot choose where a balloon lands, only roughly when. Everything about the landing — the chase crew, the farmer, the bottle — follows from that.
A balloon lands wherever it happens to be when it comes down. There is no approach path and no way to reach for a field that is off to one side; there is only the descent rate, and therefore only a choice of when, which becomes a rough choice of where by way of the wind.
Pilots plan a landing by looking a few kilometres ahead along their track and picking the best-looking option that will pass underneath at about the right time.
What “best-looking” means
Big, flat, empty, downwind of nothing tall, and — crucially — reachable by a vehicle. A perfect field in the middle of a forest with no gate is not a landing site, because a deflated balloon weighs a couple of hundred kilograms and has to leave somehow.
And it must not be a crop. A basket dragged fifty metres through a field of anything ready to harvest does real damage to someone’s year.
The chase crew
Because the destination is not known until it happens, every balloon flight has a second half on the ground: a crew following by road, watching the balloon, guessing which way it will drift, and trying to be at the field when it arrives.
This is why ballooning is a group sport whether or not you wanted it to be. Even a solo pilot needs people with a trailer.
A balloon lands on land that belongs to somebody. Asking permission — before, if the field was planned, and immediately afterwards if it was not — is not a courtesy in ballooning. It is the thing the whole activity depends on, because a region where landowners are tired of balloons is a region with no ballooning.
The champagne
Which brings us to the bottle. The tradition is that a balloon crew carries champagne and gives it to whoever owns the field they landed in.
The usual story sends it back to 1780s France, where a balloon descending out of the sky onto farmland was met by people who had every reason to think it was something dangerous, and the aeronauts offered wine to prove they were French and harmless. Whether or not the details survive scrutiny, the function of the custom is obvious and has not changed in 240 years: you have just landed a large object in a stranger’s field, and you would like to be welcome again.
Modern crews still carry it, and it is still handed over in the same direction.