From my experience, FedEx and UPS are far less reliable when it comes to timely delivery. This hasn't always been the case but definitely has been, for us, over the past couple of years. This has been a problem for our business; many more of our packages are now delayed than not. I gather the reliability is somewhat region specific; we notice from tracking data that most of the delays seem to be the result of the packages sitting extended periods of time in our region. This has been a problem even when we choose an expedited shipping option.

On the other hand, we always check a bag when flying American Airlines and we have yet to ever have a delayed or missing bag with them. I am sure some of this is luck but it probably also helps that we arrive to airports early and never actively book a tight connection . We do often have to wait a ridiculous amount of time in baggage claim at certain airport but we plan for and expect that at this point.

We do avoid flying United if we need to check a bag as we have had far too many issues with delayed or missing bags with them.