Which kind of aircraft is in the sky?
The aircraft is airplanes.
    src        edge_attr  dst
0     1   to the left of    6
1     1   to the left of    4
2     2   to the left of    6
3     4  to the right of    1
4     5               in    6
5     5               in    0
6     5   to the left of    6
7     6  to the right of    1
8     6  to the right of    5
9     6  to the right of    2
10    6  to the right of    7
11    7               in    0
12    7   to the left of    6