Christian Horner says he still thinks the new front wing regulations for 2019 were "unnecessary".
Liberty Media pushed for the design change to make overtaking easier, but Red Bull boss Horner says the actual result was a big bill for the teams.
Horner also admitted to Auto Motor und Sport that it took Red Bull longer than the other teams to get the new aerodynamic concept right.
"I think so," he said.
"Our aero concept relies heavily on the front wing, which has an impact on the rest of the car. As a result, our car was very sensitive on the track.
"It took a while to understand and optimise that," said Horner.
"The car was difficult to setup and hard to drive, but we still got some good results even at the beginning of the season."
Horner thinks the decision to go with the 2019 front wing regulations was primarily political.
"Ferrari and Mercedes really wanted that wing," he said.
"I think by now they've realised that the exercise only cost money and didn't make the races any better. In my view, it was unnecessary spending."
