FIG. 1 is a perspective view of a drone aircraft showing our new design;
FIG. 2 is another perspective view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a back view thereof;
FIG. 5 is a left view thereof;
FIG. 6 is a right view thereof;
FIG. 7 is a top view thereof;
FIG. 8 is a bottom view thereof;
FIG. 9 is a partially enlarged view of FIG. 1;
FIG. 10 is a partially enlarged view of FIG. 2;
FIG. 11 is a partially enlarged view of FIG. 3;
FIG. 12 is a partially enlarged view of FIG. 7; and,
FIG. 13 is another partially enlarged view of FIG. 7.
The broken lines shown on the drawings depict portions of the drone aircraft that form no part of the claimed design.