Prince Harry defended his use of private jets on Tuesday ironically during his launch of a sustainable travel initiative intended to transform the travel industry into a catalyst for good.

The Duke of Sussex told a crowd in Amsterdam that he and Meghan Markle , who have been criticized for promoting conservation while taking private flights for vacations, choose their transportation based on safety.

I came here by commercial, Harry said during the initiative, called Travalyst , that aims to bring consumers, companies and communities together. I spend 99% of my life traveling the world by commercial. Occasionally there needs to be an opportunity based on a unique circumstance to ensure my family are safe and its genuinely as simple as that.

The royal couple have been under fire for reportedly taking four private flights in 11 days for vacations in France and Spain. The carbon footprint for private travel is far bigger than for commercial, which critics say contradicts the couples promotion of conservation causes.