Marvel looks to be making Ant-Man part of the bigger Marvel cinematic universe by including many already established characters in a flash back to the early days of S.H.I.E.L.D.
Personally I think this is a great way to tie Hank Pym into the wider cinematic universe!
Taken from bleedingcool.com:
There is a rumor that the Ant-Man movie will have a few familiar faces in it. So let me bust out my Ant-Man specific spoiler warning…
Okay, so the rumor we are hearing is that Dominic Cooper (Howard Stark), Hayley Atwell (Peggy Carter) and Toby Jones (Arnim Zola) will be reprising their roles in a flashback scene with a younger Hank Pym. This was supposedly in the draft prior to Edgar Wright’s exit from the movie, but with Marvel wanting to tie all the movies together, a scene like this would serve well to connect Ant-Man to the rest of the Marvel Cinematic Universe.