Is altitude information included in filed flight plan?
The flight plan contains the requested cruise flight level, as well as step climbs or level changes along the route in the route field.



Example 1:

(Image Source: skybrary.aero)



Example 2:


  SAM UN621 BASIK/N0412F330 UZ150 BADUR/N0426F340 UN472 ARE/N0424F350 UN864 PIMOS


Fxxx being the requested flight level.