When I was a flight attendant and had free passes, I flew all over the place with my infant, starting at 4 months. But 4-month-old TWINS? Even with my decades of experience, I don't think I could handle that, and most certainly not on a long-haul flight. The change in pressure hurts their ears, and while there are things you can do to alleviate it (sucking on a pacifier and covering their ears with steamy cups), imagine trying to take care of two screaming babies at the same time. I really hope you can find someone to travel with you.