According to tweeter @luvkardashiansKim Kardashian, sister Kourtney and her son Mason Disick were seen taking a flight back to NYC (JFK airport) yesterday (Oct 16).The trio were returning to NYC to continue filming their new spin-off reality show, after Kim's 30th Sin City birthday bash.

Kim tweeted, "Back in NYC! What a night! I love all of my friends SO much! I have a feeling 30's are gonna be the best ever!"

Kim's 30th birthday was held in Las Vegas. Kim was joined by her sisters Kourtney and Khloe and mum Kris Jenner and brother Robert, as well as many of her friends. Kim turns 30 on October 21st.