The magnetic hysteresis was studied for YBa2Cu3O7 films of different epitaxial orientations on single-crystal SrTiO3 and KTaO3 substrates. Deposition by coevaporation of Y, BaF2, and Cu was followed by annealing in flowing, wet oxygen at 800-850°C. The critical current density Jc deduced from magnetic hysteresis loops was compared with four-terminal transport-current results. Thermally activated magnetic flux flow was manifest in the audio-frequency data. Jc fits a scaling law similar to one used for describing Nb3Sn and other A15 materials.