That's actually a pretty good way of putting it, and if one conceptualises a cheque as such, you would almost always be asking "why a personal cheque?"
Reasons for writing a check:
1) You don't have money - XX
2) You don't have money now, but hopefully will when the check is cashed - XX
3) You were born before 1930 - XX
4) You are a scam artist - XX
5) You are honest
If the airplane has a 20% chance of being on time, you should probably make alternative plans to get somewhere... and if the excuse has a 20% chance of being legit, it likely won't be ;-)
I just love my analogies, even if nobody else does, ehhe