There are two types of accounts you can have in World of Warplanes – a regular free account and a premium account, which has to be acquired using Gold (Tokens during Open Beta). In the current stage of the Open Beta, every player gets to play on a premium account for free.
Having a premium account gives you two bonuses – 50% more credits and 50% more XP after each battle. This allows you to advance through the game a little quicker, but it does not give you any advantage over the free-to-play players in battles. An active F2P-player can achieve the same level of success (or misfortune) as any Premium-player.
This means that having Premium does not give your plane some kind of magical boost. It will not make you fly faster, turn quicker or shoot more precisely. All it does is giving you the ability to level up a little bit faster, so you can reach the plane of your dreams in less time than if you had to grind your way through the tech tree without any assistance.
If you want to boost your progress to unlock planes and modules from the different tech trees quicker, then you should consider going Premium. After all, the top-tier aircraft are very expensive and will take a lot of time to reach, so getting a little help by earning 50% extra credits on all of your battles can go a long way to making the game more enjoyable for you.
Get Airborne!