(I take advantage of airline miles, payoff the balance every month).

Especially with AC systems, it has to be installed using Nitrogen during burn in of the lineset, followed by using a micron gauge to ensure proper vacuum before the freon is released into the system.

I am not an airline.

@Jason Sterner If you're specifically looking for urban areas I agree with @Nik Moushon - no regs means there's a vacuum that will get filled sooner than later.I'm in vacation markets where short-term rentals are a vital part of the local economy.  

Delta Airlines.  

When operating you’ll may want to purchase a program which projects your optimum daily rate utilizing dynamic pricing, as used by hotels, airlines, etc.

Eric,    My advise to you/your friend is to actually take a walk through the property, and try to fix the easy stuff, missing door knobs, replace light bulbs, fix the gutters, vacuum the rugs, clean the place, deodorize etc...  

Airlines keep adding new routes and hotel chains keep investing billions of dollars in new facilities.

Google “vacuum the truck” and “BiggerPockets podcast”.

I wanted to buy a robot vacuum cleaner Roomba 960, but then I found an article comparing Roomba 960 vs Roomba 980.Who then used any of these models?