Factual error: They travel on a Boeing 777 to Amsterdam. The shots in the airplane are in a much smaller cabin (3 seats/aisle/3 seats). The 777 seating in economy class is 9 or 10 seats across, with two aisles. (01:29:00 - 01:30:00)
Factual error: When Hazel Grace goes to the hospital with fluid in her lungs, her monitor shows she has 97 percent oxygen saturation. Even after the fluid was drained from her lungs and regardless of her being on oxygen, given her disease and diminished lung capacity, her oxygen saturation would have not been as high as that.