Main shuttlebay

The main shuttlebay, also known as the main bay, was the largest of three shuttlebay facilities aboard starships, located across Decks 3 and 4 of the saucer section. The shuttlebay was enormous and accessed by one roll-up door. Decompressing the main shuttlebay would provide enough thrust to move the entire ship. It was also sufficiently large enough to house three runabouts. 

Jake Kurland stole a shuttle from the main shuttlebay of the USS Enterprise (NCC-1701-D) in 2364, intending to fly it to Beltane IX and join the crew of a freighter. 

In early 2366, the Type 7 shuttlecraft Sakharov, Tereshkova, and McAuliffe were listed on the shuttlebay operations display as being in the main bay, along with the Type 15 shuttlepods Lindberg, Cochrane, Curie, and Feynman. 

The shuttlepod Ley, after traveling through the Barzan wormhole, returned to the Enterprise through the main shuttlebay. 

Worf and Data departed the separated Enterprise saucer from the main shuttlebay, while the saucer was distracting the Borg with an antimatter spread. This provided cover for the shuttle to penetrate the Borg cube's electromagnetic field and rescue Captain Jean-Luc Picard, assimilated as Locutus of Borg. 

The Nenebek left the Enterprise through its main shuttlebay. 

In 2368, Doctor Beverly Crusher ordered all three Enterprise shuttlebays, including the main shuttlebay, be converted for emergency triage operations in preparation for the rescue of USS Denver survivors. 

Later that year, the Enterprise main shuttlebay housed the Type 6 shuttlecraft Berman and Piller. The shuttles were present when the main shuttlebay was decompressed to avoid a collision with the USS Bozeman, freeing both ships from a temporal causality loop. 

Background information
Due to its size, the main shuttlebay would have been prohibitively expensive to construct as a full-sized set. It was only seen twice during the run of TNG as a wall through the window of a shuttle during (a simple reuse of the existing shuttle/cargo bay set), and as a partial miniature built by Ed Miarecki for. 

The USS Enterprise (NCC-1701-E) also has a shuttlebay in a similar location on its saucer section, used in both  and. Unlike the Enterprise-D, it featured segmented doors as opposed to one large door, and was not identified as the main shuttlebay in dialog.