I work for an airline where I get to fly to Jaddah and spend one night there. I usually arrive at twelve am, unless there was a delay in the flight or at the airport. Sometimes, I arrive at the hotel on time and make the intention to perform Umrah from there, so I assume Ihram (Ritual consecration), go to the Haram (Sanctuary) and perform the Umrah. However, I don`t assume Ihram, while on board, from the Miqat (Place of assuming Ihram) because my flight may not arrive on its scheduled time or because I`m in uniform. Is the Umrah that I have offered valid although I didn`t assume Ihram from the Miqat, I made the intention to perform Umrah when I arrived at the hotel and I checked that I had enough time between flights? Moreover, I have performed four Umrahs in this exact manner, are they valid or not?