Anyway, I am hoping that this will help me, and help you, keep mental track of the mainstream airliner families of the two biggest manufacturers: Boeing and Airbus.
Lefter shorter, righter longer (comparing the longest variants). Some of these they don't make anymore, but you might still see them in the wild.
717**, 737, A321***, 757
A310, A300, 767, A330, 787, A350, 777
Dual-Aisle, Four-Engine, Single-Deck
Dual-Aisle, Four-Engine, Double-Deck
* - Well, they sort of do so now, but they got there by skipping 7, 8, and 9. Vista through 8.1 were version 6.x Windows.
** - Formerly the MD-95.
*** - The A318 through A321 are known as the A320 family. As you might expect, the A318s are the shortest and the A321s are the longest.
**** - The A380 has much greater interior volume than the 747, as its upper deck extends the whole length of the aircraft.