This is in response to >>1813284. I’m a classic car fan, so I tried to come up with some different choices I thought would suit their personalities.  
Princess Twilight Sparkle - Stout Scarab. Innovative, logical, and plenty of room for her to get her royal business done while Spike drives her around Equestria on friendship business.  
Pinkie Pie - Davis Divan. A fun and offbeat three-wheeler for her.  
Fluttershy - Volkswagen Type 14A “Hebmüller”. The friendliness and charm of the VW Beetle combined with a lovely two-seat cabriolet body by Hebmüller.  
Rainbow Dash - Muntz Jet. Cadillac V8 in a Kurtis-built chassis. In the postwar years, it was one of the fastest cars you could get.  
Rarity - Voisin C27 Aérosport. A masterpiece of French Art Deco design. A literal one-of-a-kind, just like Rarity herself.  
Applejack - Hudson Big Boy. Stylish enough for Rarity to be seen in it, strong enough for Applejack to get her deliveries done in it.  
Twilight Sparkle - Tatra T87. Just like her pony counterpart, Sci-Twi is drawn to large, comfortable, aerodynamic vehicles. The Tatra has a rear-mounted, air-cooled V8 which appeals to her scientific mind.  
Sunset Shimmer - Alfa Romeo 6C 2500 Villa d’Este by Touring. Fast, beautiful, a little wicked.