What are the slips of paper the ground crew hands to the pilots before take-off?
Are fuel tanks always topped off before flight? Or are they purposely left a little empty depending on flight distance to save weight?
What kind of mark up are you getting on liquor/beer on these flights? $5 beers!!???
What’s the best way to get an upgrade? Schmooze a better seat, or get a bike case on for free? Are gate/ticket agents bound by rules or do they have alot of leeway?
#1. One slip of paper is fuel upload. The captain derives his CG (center of gravity, which I’m sure you alreay knew 
from that one, from the MGL (showing total weight, including fuel, passengers, cargo…everything) and from another document which gives a figure for that particular plane. These numbers are all calculated onboard, and back in Load Control here in HNL and in SOC (System Operations Center) in Minneapolis. His final control surface settings are received via his ACARs system and away he goes. There’s a decent-sized margin of error built into his CG figure, for obvious reasons, though we do have 3 categories of “load error” (C, B and A…which is the worst). None of the 3 are capable, though, of causing a large jet aircraft to experience the kinds of incidents that you might be pondering, though 
#2. Fuel upload varies by aircraft type, particular trip and other factors such as weather, cargo weight etc. Most pilots in our company fly with between 5 and 10% extra fuel needed “just in case”. In my experience, especially with domestic flights in the lower-48, most planes don’t leave completely “topped-off”. This is mainly because the combination of fuel, cargo and passenger weight (from which we derive the standard weight & balance final number) all interplay in a delicate grouping.
#3. All of the food, beer and liquor sales are handled by our Inflight, not Ground Operations, people. Most is from our contract caterer (out here in HNL it’s Gate Gourmet…elsewhere it could be LSG Sky Chefs or some other outfit). Marketing, Inflight and Accounting all sit down and figure out what it is that we’ll charge for that stuff, though obviously, any airline is always trying to squeeze maximum revenue out of these “extras” nowadays Most managers keep an “amenity coupon” book, with comps for movies, liquor, beer, headsets, extra miles and stuff. We pass 'em out whenever we’ve got a customer service situation to deal with.
#4. The gate/ticket agents always have some leeway, though we, as management, are required to monitor what we call “undercompensation”, or instances in which an agent will not collect all of the revenue which he or she should’ve collected from the passenger. An excess bag charge to a main cabin passenger (not a WBC or First Class passenger) is one that almost is impossible to get right 100% of the time. Likewise, an excessively large (“cubed out”) bag that is non-standard sized or is over the 50 to 100 pound limit that most airlines place on bag weight. We don’t normally accept a bag that weighs 100 pounds or more, and we have a set fee, per each 25lbs. over the 50lbs. limit. This is mainly due to the inordinately large amount of back injuries and such that we experience from our agent/ramp service labor groups when it comes to lifting these heavy bags. On a 757 and below (Airbus A320/319, DC-9, ARJ), the bags have to be manually loaded into the belly of the plane. Very backbreaking work, sometimes, especially if the worker fails to properly observe proper back procedures. 
From past experience, most airline agents tend to be more accommodating to First Class or full-fare coach passengers. The leisure, or tourist, passenger, who’s paid something like 130 bucks for a roundtrip ticket Detroit-to-Orlando and back, doesn’t quite get the same amount of leeway when it comes to things like bike cases and such. In a perfect customer service world, ALL passengers would be treated with the same level of consideration. But if that were the case, we wouldn’t have such a thing as First Class, or elite status for frequent fliers Also, a big reason for the bike charge has to do with the large amount of claims filed by passengers traveling with bikes. I’m not defending it, because I go everywhere with my bike, and if I wasn’t an airline employee I’d be paying that same charge. I’m just pointing it out, is all.
K