That was the case this week on a Delta Air Lines flight I took from Grand Rapids to Minneapolis on my way to Mountain View, California, for Google I/O. Because of weather over parts of the Midwest, a thing that regularly disrupts travel in these parts, our flight was delayed at the gate for an hour or so.

No oil was visible in the gauge on the right engine’s oil reservoir after a February Delta Air Lines flight filled with smoke during takeoff at Atlanta’s Hartsfield Jackson International Airport, a preliminary report from the National Transportation Safety Board said Wednesday.

After a Delta flight made an emergency landing in Atlanta​ in February, a maintenance crew found there was barely any or possibly no oil in the aircraft's right engine, an NTSB report said.