It's showing at 1080p for me on Vimeo. Nice work, Mike. Something you may want to consider if you are going to keep shooting and editing video is a set of neutral density (ND) filters). These artificially lower the amount of light that is getting to your camera's sensor, letting you control the shutter speed.
The general rule of thumb is you want to be shooting at a low ISO (ISO 100 on your P4) and at a shutter speed that is about 2x your frame rate per second. So if you are shooting 1080p 30 frames per second at ISO 100, you would need to use an ND filter that would get your shutter speed down to about 1/60th of a second. I can tell you from experience that on a sunny Southern California day, that will be an ND32 or even ND64 filter. On a cloudier day you might need an ND16 or ND8 filter, as those let more light through. You don't have to spend a fortune on a filter set. I have a very affordable set that suits my amateur needs very well. Surprisingly, a lot of of the more expensive sets don't go above ND16 or maybe ND32. I don't know where these guys and gals are filming, but I don't think it can be Southern California!
What you want is just enough "motion blur" on moving objects like cars, birds, etc. (and the ground if you are flying low) that the video looks natural to the eye. Hence the "2x the frame rate" estimate. It's not like you have to have those filters, but something to consider for a future investment. A YouTube search will find you examples of the difference with and without.