There have been a lot of rumors about whether Ant-Man will turn into his larger alter ego from the comics and become Giant-Man during Captain America: Civil War. It seems that Funko's Pop! Vinyl Figures have dropped the news sooner than expected:
I found this figure at my local Barnes and Noble and I'm sure it can be found at your's as well.
The figure proves that at one point in the movie Paul Rudd's Scott Lang will transform into Giant-Man. It would not be the first time that action figures and toys have spoiled movies, this is not even the first toy to spoil the Ant-Man twist.
Lego also revealed this set that shows an Ant-Man that is much larger then the other characters. While this one does not explicitly say "Giant-Man" it is heavily implied. It appears from this Lego set that at some point during the big fight scene at the airport is when we will see Ant-Man turn into Giant-Man; perhaps as a trump card for Cap's team to take down Iron Man's.
Sometimes toy sets do tend to stray away from actual film events, so this Lego set could just be another marketing tool. The Pop! figure is different; Pop! rarely makes figures that they market as being from a certain movie and then that character does not actually appear.
It makes you wonder how Scott is going to be able to grow in size since it was never implied in Ant-Man that Hank Pym has never used the suit for growth. We saw Scott use the blue Pym Particles to grow out of the Negative Zone, but the concept of Giant-Man was never discussed. It will be interesting to see how they incorporate it into the story.