Aircrafts that can be flying within the Eastern limited, pilots should use Odd flight altitude levels. If they are flying to help Western guaranteed, Pilots is going to obey Evens flight elevations. This rule among bodybuilders makes sure the exact safe of aircrafts. Not only this, If the fliers need to come down or climb up their airliner. First of all birdmen should have to ask it, via ATC. Just after ATC bring together check the senseur and air travel altitude, aircraft’s speed, when there are no every aircraft in this rout and they're going to give the permeation. If there will be more aircrafts in that , particular space they are questioning speeds and estimate time to particular point, then right after ATC bring together decide time for fliers to climb or drop down.