In this video at 7:04 we see the following view of a VC-25 (an aircraft frequently known as "Air Force One"):
What are the two shiny, gold-coloured structures above and to the rear of the engine exhaust?
Aviation Stack Exchange is a question and answer site for aircraft pilots, mechanics, and enthusiasts. It only takes a minute to sign up.Sign up to join this community
According to a comment on the video from Jamie Lancaster:
Behind the engines under the wing are the 2 IRCM (Infrared Counter Measure) Jammers - for Air to Air or Ground to Air Missile Defense.
In the comments below, GremlinWranger suggests that it's likely a descendant of the Common Infrared Countermeasures Program based on the appearance of the ALQ-144, which does indeed have similar mirrored panels.
A bit of further searching turns up this blog entry which claims to show pictures of the AN/ALQ-157 which is even more similar looking, particularly in its four-facet design with hemispherical coverage. (That page also has a reduced-size German poster explaining "Air Force One," by which they mean the V-25, but the relationship of that to anything else in the article is never explained.)
It is a decendant of AN/ALQ-144 and similarly is designed to defeat first gen MANPADS