The distance covered by the airplane in the first 30.5 seconds can be determined by calculating the area under the velocity-time graph.

The formula for distance in this scenario is:

$ \text{Distance} = \text{Area under the graph} $

Calculating the individual areas:

$ 300 \, \text{m/s} \times 2 \, \text{s} = 600 \, \text{m} $

$ 400 \, \text{m/s} \times 28.5 \, \text{s} = 11400 \, \text{m} $

Adding these values gives the total distance:

$ \text{Total distance} = 600 \, \text{m} + 11400 \, \text{m} = 12000 \, \text{m} $

Thus, the distance covered by the airplane in the first 30.5 seconds is $ 12000 \, \text{m} $, which is equivalent to 12 km.