Snoopy wrote:
Yes, but why?
In order to fly in the cabin, the fly needs to deflect air molecules downwards which will eventually cause a downward force on the airframe, which is equivalent to an increase in its weight by the amount that the fly weighs. This is actually a well known thought experiment in Newtonian mechanics.
zuutroy wrote:
In order to fly in the cabin, the fly needs to deflect air molecules downwards
Lindbergh spent an hour or so thinking about it on his transatlantic flight and came to the same conclusion
the fly needs to deflect air molecules downwards
Cool, thanks @zuutroy, getting to it now.
I was for myself coming to the same conclusions…
Now assuming air molecules in a standard ISA mass, what does happen to your very thrusted craft when mentioned trapped fly jumps from a hot air ballon itself descending at 0.87619 m/s, using a wingsuit with a glide ratio of say typical 2.5/1, and then the same stupid (?}) fly, overcome by the urge pulls its sneezer, pardon me, handkerchief, to dampen the urge. The reaction of the unavoidable Covid sneeze will be so ever closely related to E=mc2 and will probably counter its descent by say a factor of 0.00756.
Now what will, from now on forever famous PAX fly, mass I ask?
What about open cockpits? 
Now we’re getting somewhere
Good question. All cockpits are open to one extent or another, or you’d suffocate. Your Turbulent isn’t the fastest in the sky (or the slowest) but I would argue that if the fly is managing to keep up then it’s in a parcel of air that is associated with the aircraft.
I would argue that if the fly is managing to keep up then it’s in a parcel of air that is associated with the aircraft.
Indeed, flies don’t fly at 80kts, so if it stays inside the cockpit, it goes into aircraft weight, if it flies away, it’s not included in weight 
Does not apply to “lighter than air” open cockpits though, otherwise you should count in Balloon MTOW with every bird & fly drifting along in the same wind
Perhaps not, but a fly buzzing around within the basket… perhaps.
Peter regularly jokes that UK airfield cafés fry their food in used 15W50. I remember watching a documentary in the 1990s where the Texan oil well owner said, “look how light this stuff is, you could put it on your salad.”
So, my question: can you use motor oil in your meals?
Oil itself isn’t toxic, and should go through the body without reacting with anything. Does the composition change if the olives are fossilised instead of freshly-pressed? I assume straight mineral oil is healthier because it has fewer additives that would react with the body, but are these harmful in vinaigrette quantities?
I would expect any modern motor oil to be highly toxic, not because crude oil itself is toxic but because of the nasty additives they put in.
Perhaps you could ask any UK airfield cafe
