My uni has travel policies out the whazoo. One of which (and I kid you not) is that we are not allowed to charter a hot air balloon without permission.
I believe you. I once took a how-to-fill-out-the-travel-request-form workshop for one of my jobs and was given the procedures to:
1) get a burro ride approved if that was the most reasonable form of travel
2) get local bribes approved and reimbursed if such was needed for access to work sites
3) get a boat rental approved, again if that was the most reasonable way to travel
I personally know people whose travel and field work has required not only baksheesh but also boats, rafts, canoes, helicopters, snowmobiles, skis, yaks, and human porters (other than grad students, that is), not to mention assorted climbing harnesses, ropes, ice axes, and whatnot. I have no idea how they got the forms through. I've never expensed anything more exotic than boots.
There are no hot air balloons on that list, but I have a piece of equipment we designed to launch on an unmanned balloon. The experiment would actually work better in some ways on a manned flight, and now I am feeling some temptation to write a small hot-air ballooning proposal.