To their surprise, the German cops found a stash of around 5,000 ecstasy pills hidden in the car.
The pills were found in plastic bags, together with a large amount of cash.
The ecstasy pills all came in the shape of the face of US President with the words 'Trump' and 'NL' written on the back.
All the pills were aptly coloured in the same tint as the American President's infamous orange hue.
Local media reported that the car had Austrian number plates.
The suspects said they had travelled to the Netherlands because they were interested in buying a car, but had returned empty-handed to Germany in the direction of Hanover.
The police, however, suspect them of having bought the pills on the Dutch market for around €11,000 ($13,000).
Both father and son were arrested while the drugs, money and their car were seized.
Dutch-made Donald Trump pills have been showing up for some time on the UK market, according to reports.
On the darknet, they are sold with the slogan 'Trump makes partying great again', referring to the famous slogan of the American President, 'Let's make America great again'.
The A30 Motorway which links Amsterdam with the German capital of Berlin and the Polish capital of Warsaw is often used by drug smugglers and other criminals.