According to a report by Cinefilos.it, a dropship is on set and is part of some kind of rescue mission involving Hawkeye, Quicksilver and the Scarlet Witch. Ultron is reportedly who they are escaping and he is not happy since some explosion sequences are allegedly planned for the Italy shoot soon.
Check out some set photos, especially the one of Quicksilver with silver hair, from the set of the Avengers sequel.
UPDATE: More set photos added of Hawkeye, Scarlet Witch and Quicksilver on set in Italy.
(Image sources: MCU Facebook, MCU Facebook, SuperHeroHype, SuperheroMoviesNews Facebook, SuperHeroHype)