So according to the reveals in the finale, Scootaloo does NOT have a physical handicap, at least not in the normal sense. She doesn't fly because of small wings, but from a deficit of magic.
Flying and scooting
Unlike most foals her age, Scootaloo hasn't been able to master flying. In Ponyville Confidential, she flaps her wings to no avail when she falls out of a tree. Despite her limited flying skills, she is able to masterfully use her wings for propulsion and various stunts on her scooter.
Our first and most beloved disabled pony is Scootaloo, daughter of an adventurer couple and one of the three original Cutie Mark Crusaders. Her wings are underdeveloped, so she can't fly. It is also shown that when she grows into a full-grown mare her wings will still remain unchanged.
It's just a visual cue to show that her wings still aren't strong enough to let her fly.
Yep, it was established in the season 4 finale that without magic pegasi cannot fly, like when Tirek took the magic away from the attacking Wonderboltz.
Mystokinesis: Alicorns are able to channel magical energy using their horns and use it to cat spells, levitate objects, and teleport.
Alicorns are long lived ponies who have both a horn and wings and the magic of all three kinds (Earth Ponies, Pegasi and Unicorns). Though exceptionally rare, any pony kind can become an Alicorn through accomplishing an impressive feat, usually in the realm of magic ability.
In Dragon Quest, she again displays her fear of dragons. Fluttershy pointedly refuses to watch the Dragon Migration with her friends, despite Twilight's coaxing.
The cutie marks on the toys of the My Little Pony Friendship is Magic toy generation sometimes do not precisely match their design on the show. Additionally, while the show features cutie marks on both sides of the pony, the toys feature the marks on only one side.
Twilight Sparkle represents the Element of Harmony magic, and she is an alicorn princess, which is a pony who has both wings and a unicorn horn.
Rarity is a white unicorn with dark blue eyes and a curled indigo-purple mane and tail. Her cutie mark, a trio of diamonds, represents her talent for prospecting gemstones and her love of art and beauty.
Scootaloo who is a pegasus pony is related to Cheerilee (in G3) who is a earth pony. This means that either Scootaloo is a adopted orphan like the theory above or pony family's can be multi pony type. This has been confirmed as of season 2, episode 13 Baby Cakes.
Scootaloo is the sole daughter of two explorer, Snap Shutter and Mane Allgood. Although her parents love her, they're not at all involved in Scootaloo's life and instead, Scootaloo lives alone with rotational supervision from various adults in Ponyville, such as the Cakes.
Rainbow Dash is a female human, a student from Canterlot High School, and electric guitarist/lead vocalist for the Rainbooms. She is one of the main characters in My Little Pony Equestria Girls. She represents the element of loyalty.
Justice League of Equestria series: In the story "Mare of Steel", while Rainbow Dash doesn't discover her true heritage until adulthood, she's known since she was a foal that she was adopted by Firefly and Thunderhead.
Rainbow Dash is the mid youngest. She's mature enough to be loyal to her friends, and she loves being awesome. Pinkie Pie is the second youngest.
Her cutie mark is a pink-and-blue lightning bolt with a yellow crown on top.
Get to know Sunny Starscout: an adventurous pony from Maretime Bay. When Sunny brings magic back to Equestria, she is transformed from Earth Pony to Alicorn!
Philomena is Princess Celestia's pet phoenix, residing in Canterlot and introduced in A Bird in the Hoof.
Hondo Flanks, also known as Magnum, and Cookie Crumbles, also known as Betty Bouffant, are the married unicorn parents of Rarity and Sweetie Belle. They appear together in Sisterhooves Social, Inspiration Manifestation, and one issue of the IDW comics, and Hondo Flanks appears alone in One Bad Apple.
While "Dash" and "Sparkle" can be assumed to be the last names of Rainbow Dash and Twilight Sparkle, Tabitha Saint Germain has said in 2018 that Rarity doesn't have a last name. She only has one name, like Cher.
Then the time skip happens and as said about the cmc- they have the adult model as they also look like teachers at Twi's school, which makes them over 20. Meaning at least 15 years passed so the mane 6 are like 45.
Appearance and Abilities. The synthetic alicorns (or alicorn drones) are all female (even though both male and female ponies can be turned), with no cutie mark.
Unlike Twilight and Cadance, Flurry Heart is a natural-born Alicorn; Celestia remarks that "the birth of an Alicorn is something Equestria has never seen".
Celestia and Luna have it because it takes massive amounts of power to raise the sun and moon. Cadence did get a flowy mane once, in the last scene of A Canterlot Wedding (when she and Shining Armor banish all the changelings).