I worked at Opa-Locka Airport during the early '80s, at an executive terminal / maintenance facility named Miami Aviation Corporation - they owned (or leased) two of the three main hangars in the photo - the one with the control tower attached, and the one in the middle.
The U.S. Coast Guard occupied the last one (the one with the darker roof in the photo). At that time they flew the Falcon jets and the Dolphin helicopters out of that facility.
I recall that there was a blimp / dirigible hangar on the premises as well - to the east (right side of the photo), I believe the rectangular area of concrete just northwest of the cloud in the lower right corner.
Many of the original runways are no longer used but still evident - in the upper right corner, and at the center left, while R30 / 12 is relatively new.
The company I worked for (M.A.C.) was not only an FBO, but specialized in DHC-6 Twin Otter maintenance, so we saw a lot of traffic from small, Latin and Caribbean-based airlines coming in for service.
has also been used by chop-shops...places that dismantle old aircraft...for many years. I believe it was the final resting place of the Lockheed Constitution (someone correct me if I'm wrong) So, it has been a good airport to see such old aircraft, but unfortunately it also been a place to see them torn apart...
There is a little bit of history detailed on the Miami Dade Aviation website - http://www.miami-airport.com/html/opa-locka_facilities.html.
May I also express my appreciation to DB777 - Don Boyd, someone who I have never met, but have admired for many years for his knowledge of aviation, and especially Miami aviation history, and whose photographs I have also admired for many years. His detail of Opa-Locka history above does much more than the little bit of history Miami-Dade provides in the link I furnished. Thank you, Don.