Passengers were urged to check their flight status before heading to the airport.
Medication and liquid baby food are exempted from the liquid rules.
According to the police, incendiary bombs containing white phosphorus were used on a large scale during World War II.
Passengers advised to check the status of their flights online before travelling to the airport.
Mr Charles, who visited Germany about 40 times before becoming king, gave his dinner speech in German and English.
Frankfurt Airport expects to deploy the new employees in September.
