Turkey's current leadership is the most politically-corrupt in the region, and in its own history. We should all be aware of the dirty role it is playing. Such accusations about the airplane cargo should be taken seriously and investigated by a third party, because making such a false claim is far more dangerous than actually transporting the weapons to Assad regime.
U.S. warns governments, bankers Iran sanctions still in place (Reuters)
from the article: Turkish PM: Syria-bound plane was carrying ammunition for Assad regime