Three flying triangle objects flying, then disappeared.

As I was driving Eastbound (North) on I-4 towards the Orange City/Deltona exit, I saw three silver triangles in the sky reflecting the sun. I pulled over to the exit lane to observe. They flew in a triangle pattern going towards the west and the objects were at an angle thus reflecting the sun. All of a sudden, they all flattened out so I could definitely see their triangle shape. At that point they were more flat grey in color. I did not notice any lights on them. Right after they flattened out, they totally disappeared from the sky. It appeared as they either became invisible, or moved so fast that they disappeared! After that, I did not see anything else. They were flying lower than a plane and slightly higher than a helicopter.