It is very difficult to make a blanket statement as to what vehicle is flat towable or not.
Thing is, most vehicles - especially those with automatic transmissions, change from year to year as to their flat tow capability; and even then, some engine/transmission combinations may or may not be flat towable for a particular model year.
For example; the current model Cherokee, it is available with 3 different automatic transmissions; 2WD, 4WD, and 4WD dual range. Of the three transmissions, only the 4WD dual range transmission can be flat towed (it has a transfer-case neutral switch). The dual range is standard on the Trailhawk, and a $1,000 option on the others (caveat; that was as of 2014 when we looked at Cherokees for a toad. Things may have changed since then).
You need to do some research before deciding to tow a vehicle. Most manufacturers have a "Recreational Towing" section in their owner's manuals that tells you whether the vehicle is flat towable behind a motorhome, what engine/transmissions may or may not be towed, restrictions (speed or distance), as well as any setup required (procedure to place the transmission in neutral, removing fuses, etc).
The point I am trying to make is a particular model year or transmission/engine combination may or may not be flat towable for any given vehicle model. It changes all the time. One of the most popular toad models; the Honda CR-V with either manual or automatic transmission was flat towable from the beginning of time... until the 2015 model year when Honda started putting CVTs in them. They are no longer flat towable.
As of now, only a very few late model vehicles are flat towable, especially those with automatic transmissions; and I suspect this list is going to be less and less as manufacturers strive to meet future CAFE fuel economy standards. They are looking to shave every ounce of excessive weight from the vehicles to meet new mileage standards, and thus are removing components (e.g. transfer case neutrals) that make them flat towable.
As well, some have found certain models, although the owner's manuals state they are not flat towable, have found they tow OK. Websites such as www.remcoindustries.com
do have an index that details those vehicles.
However, you may be at some risk if the owner's manual states a vehicle is not flat towable and you use the advice from remco and damage your vehicle; especially if the vehicle is still under warranty. Said warranty might be void if you flat tow against the owner's manual instructions.