Kate Middleton takes solo trip, leaving 'sad' Prince George and siblings behindPrincess Kate carried out a royal engagement on Thursday. View 5 Images Princess Kate hopped into a flight simulator during a recent visit to the Royal Air Force (Image: Getty Images)Prince George, Princess Charlotte, and Prince Louis were reportedly "very sad" when their mother, Princess Kate, embarked on a solo royal engagement on Thursday. Kate mentioned the Wales children during the royal engagementPrincess Kate reportedly discussed this during her visit yesterday, echoing a sentiment previously expressed by Louis. ‌View 5 Images Princess Kate reportedly discussed this during her visit yesterday, echoing a sentiment previously expressed by Louis. Surprisingly, William mentioned Prince Harry during the episode, which is the first time he's spoken about his younger brother in ages.