Sure it can be done. But the payload would be non-cost-effective. Won't happen in practice. can be started up and run at low speed = "lack of thrust" Also,

Sure it can be done. But the payload would be non-cost-effective. Won't happen in practice. can be started up and run at low speed = "lack of thrust" Also, liquid hydrogen takes up around four times the space as the same volume of kerosine = no space for passengers. (There is a practical limit to the physical size of aircraft in today's world. To go larger, we'd need to scrap the existing airtports and rebuild with new larger expensive ones.)