Bought the 90K plane tonight , whan i bought it it worked fine. But when i got up this morning and joined a fight it barly could get of ground , reached close to 100 in speed , couldnt climbe before the speed droped at once.. any suggestion on what to do.??

Start upgrading it.
With the exception of the freebie tier 1 planes the planes don't come fully upgraded and so you need to purchase speed & maneuverability & armament upgrades for your plane.
Just click the top row of icons when you choose your plane for a mission and they will explain each item and advise you when your plane is fully upgraded in each category.

Ty for ur answer..
But its strange the plane is so bad in the beginning , so u need to upgrade it just so it can fly.
Yesterday when i bought it i had a top speed of around 150 and now its 100.. and bearly possible to keep it flying straight in the air before it fall down.. hmmm.. dont like that at all..
Even the first plane in the hangar we get is bether. WHY.