Answer
Please see the work below.
Work Step by Step
We know that
$\Delta =\frac{\Delta t_{\circ}}{\sqrt{1-\frac{v^2}{c^2}}}$.
The airplane which has clock 2 has the greater speed and the value of $\sqrt{1-\frac{v^2}{c^2}}$ decreases; as a result, the value of $\Delta t $ increases. This shows that the difference between two successive events is increased and hence clock 2 runs slower as compared to clock 1.
