The gas station seen at the beginning was a Roxxon station. Roxxon is a fictional energy company in the Marvel Universe. Roxxon is often depicted as corrupt and at odds with various Marvel heroes.
The UpWords board in the end scenes shows the words "strange" and "tales." Strange Tales is the comic book where Nick Fury, Agent of S.H.I.E.L.D., debuted.
The call-sign for The Bus is "S.H.I.E.L.D 616". 616 is the allocated number for the mainstream Marvel universe named Earth-616 in the Marvel comics continuity.
First appearance of Agent Davis, who becomes a regular in later seasons