First Contact

After winning the duel against Trixie,

Trixie heard what sounded like a camera flash going off. Then Twilight watched four figures run down the nearby hill. Trixie ran after them, and saw a strange aircraft there. Everypony saw the craft fly over them after it lifted off. It had a tail on the back, with a propeller, and one bigger propeller on top. They realized it was a helicopter, because the writing on the side, said "Exploration Helicopter". They notified Celestia at once. Neither she, nor Luna could understand what they were talking about. They had seen the vehicles, but never saw the figures. Eventually, they'd had enough, and ordered notices to be put out. They placed "WANTED" posters all over Equestria, hoping that if the figures were seen, they could be caught, and brought to Canterlot.

3 weeks later,

There were reports coming in that some of the posters had been either torn down, or destroyed. Celestia was irritated, and she searched the places where it was happening. She found a note where one poster had been.

It read, "Your Majesty, We do not mean to invade your land. We are harmless explorers, searching the far reaches around us. Signed, Anonymous."

Then, Celestia understood what was really going on, and cancelled the posters.