flat and is covered by a grid 3 which is aligned in a north south direction towards the magnetic poles for example the distance between the grid lines is preset and in a preferred embodiment of the invention can be switched between one nautical mile and one geodetic minute of arc in the representation of fig1 the aircraft is flying very low so that only a few grid lines are visible in contrast to fig3 to 6 since in the perspective representation the number of grid lines is very large in the region of the horizon it would be necessary without further measures to calculate very many grid lines which could no longer be represented anyway for reasons of resolution no more lines are therefore calculated and represented in a surface region 4 in front of the horizon but this surface region 4 fig3 to 6 is provided with a colour which is matched to the colour effect produced by the colour of the ground and by the lines of the grid becoming closer in the examples of embodiments illustrated the precalculated flight path is represented by triangular segments 5 to 8 in this respect the individual segments 5 to 8 represent the precalculated position the altitude the course and the air position of the aircraft respectively the sum of the segment shaped symbols 5.