Oak 1 was a G-rate transport coach, a type of Federation shuttlecraft assigned to Starbase 10's Oak Squad of security personnel in the Starfleet Special Services division. Oak 1 was a large variation of Starfleet shuttle design, landing-capable, and was equipped to carry about 40 persons at warp speed, with amenities for civilian dignitaries and Federation diplomats. The coach shuttle had a detachable midwing defense craft, known colloquially as "the frog".
In 2353, Oak 1 was commanded by Ensign Eric Stiles, who took the craft and its fighter escorts to the planet PojjanPiraKot to rescue twenty Federation embassy personnel who were ordered by the Pojjana government to leave that world. Stiles was surprised to find thirty-five civilians waiting to be escorted by his seven-man rescue team, but the Oak 1 coach fit them all aboard. Stiles detached the midwing in order to confront a Pojjan aircraft that was pursuing the coach, he was able to give Oak 1 time to achieve space altitude by ramming a Pojjan assault interceptor aircraft. Oak 1 escaped, with Ambassador Spock at its helm, and the sturdy midwing survived, crashing Stiles on the Pojjan surface. (TNG - Double Helix novel: Red Sector)