LOL.
"ErRrR pOiNt tO Me iN yOuR..,."
Let me spell it out for you.
The achievement being reported is that the plane performed a 30 minute flight. The implied details being that it took off, flew around in circles, and landed again at the same air port.
The distance the plane traveled is not the achievement and it's not relevant.
Is there a lift vs drag problem that precludes making a glider with such a heavy payload? It might not be as simple as bigger wings to support the heavier weight.