Chris Roberts & John Pritchett write an absurdly-detailed post on flying in Star Citizen.

Clocking in at over 4,000 words, this is a real meaty transmission.

Arena Commander, the Star Citizen dogfighting module, was recently added to the game.
A few fighters felt the physics weren't feeling right, so Cloud Imperium CEO Chris Roberts and Physics Programmer John Pritchett have transmitted a detailed explanation of the game's flight model and input controls – graphs included.

tl;dr: Ships move the way they do because Star Citizen is a true simulation. It simulates how your ship would move in space, and every element of your ship has a real effect on its behavior.
 

Here's a collection of quotes that merely skim the surface:

"Star Citizen's physical simulation of spaceflight is based on what would actually happen in space."

"... you need to anticipate where you want to be and ease into that position. If you're used to an atmospheric model when first flying in a model where momentum is much more important it is pretty easy to overshoot your desired heading."

"I felt we needed a simulation that would let the player have different flight behavior if a thruster is damaged, a wing is blown off or a pilot overloads his ship with weapons and ammunition."

"Ship load out becomes very important not just for functionality but also for actual flight and responsiveness."

And just something really fantastic about Star Citizen:

"Every function (of a ship) is tied to individual items that are "plugged" into the ship ... If there aren't enough CPU cycles to go around the targets will resolve slower, not enough power and the targeting computer may stop functioning all together. If you don't draw off enough heat from the weapons, they may overheat, malfunction or even become damaged. If one of your wings gets blown off with its attached heat sinks, you better scale back your heat output."

To get an idea of Star Citizen's movement, check out the behavior of this ship from 0:20 to 0:40:

Colt "ShdwFlm" Casey
Deputy Editor