Another great example using ZFV, I just booked a flight to YVR, leaving this Tuesday. The airfares were over $900 but google flights showed the ZFV option. However, when I clicked through from google flights, I kept getting an error message and couldn't complete the transaction. I called United and they said that it was a known issue with google flights. However, I persevered and just entered ZFV as the departure city and managed to book the return flight to Vancouver for $165. I now have to travel to Philadelphia when I would have just gone directly to Newark but it is worth the saving.