I just wanna know which is better, as Im a teenager and just need it for daily use & occasional movies.
For movie's I would look for the best screen, and that is the Retina.
MacBook Air screens aren't Retina displays, so the pixel density is lower. The 13-inch Air has a native 1,440-x-900 screen resolution compared to the 2,560-by-1,600 resolution on the 13-inch MacBook Pro with Retina. That is nearly double the resolution in both axes as the familiar 1,280 x 800 size, and hits a pixel density of 227 ppi (pixels per inch) that makes individual pixels invisible to the eye at reading distances.
The MacBook Air features a LED-backlit display, but only the Retina MacBook Pro adds IPS technology to this. The IPS panel means very wide viewing angles and richer, more accurate colours.
You will notice the differences between the two screens, so if you want the best quality screen the Air will not be for you.
2015 Retina MacBook Pro features Intel Iris Graphics 6100 which is better than the 5000 of the older model, but will still hold back 4k through its HDMI outlet. The Air has an Intel HD Graphics 6000 which is slightly inferior runs Batman: Arkham City benchmark test,t2015 MacBook Air averaged 29 frames per second , where as the Pro ran a reasonable 35 fps.
Battery life is where the Air excels at around 12hrs usage, however the Pro has recently caught up and is just above 10hrs.
Storage, comparable priced Pro will only have a 128Gb SSD to the Airs 256Gb, you would be advised to up grade this to 256Gb but it will cost another $200. However the Air only comes with 4Gb RAM upgrading that which I strongly advise will cost another $130. So the equivalent spec'd 8Gb Ram & 256Gb SSD are about the same in price.
Having said that, you are probably going to either stream or run the films of a thumb drive so not relevant,( but I would still advise upgrading as SSD's prefer being partially filled for wear levelling to work properly thus extend its life).
That really just leaves size & weight. Surprisingly the Air is only actually 1mm thinner than the Pro, the Air appears lean due to its tapered edges.
Weight is where the Air finally scores coming in at 0.92Kg vs the Pro's 1.58kg.
Considering all of the above, I would go for the Pro with its superior screen, graphics chip & processing power. All of this will make it more future proof than the Air. The advantages of 2hrs extra battery life & 0.5kg weight the Air has, are not exceptionally better, for me to consider it as must have reasons.
I hope this helps.