First off, the person who shot this video does a horrible job holding the camera steady, consequently it is difficult to watch. That said the video is quickly going viral, as to it content, it is easier to say what it is most likely not rather than what it actually is.
It is not a conventional airplane, I do not believe it to be a ship on the horizon and is certainly not lanterns. I did find a second video that was obviously shot later that same day, so whatever it was stayed in the area for quite some time. (you will find the witness comments below)
For related visuals... watch these Videos...
Posters Comments: "About 21hs Day 14/01/14 could see this from the coast of Monte Hermoso. Searching the Internet, it is called a meteorite in Buenos Aires on 12/01, one in Saltillo, Mexico and San Antonio, Texas on 11/01."