I think almost any other airline I've flown on is 24 hours. DL, EK, LX, LH, SN, SK, RO, B2, LO, VS, BE were all opened at that time and that's just off the top do my head. I think BD used to be the same too. There may be some variation between if you pay for seats or not before then, but the actual check in doesn't open until much closer to the flight than Ryanair. Yes, they don't charge to do airport check in (Yet!) but it's still a short time frame when compared to some low cost carriers.