These are fares for “flights” to or from ZFV. If you’ve been to a DansDeals seminar you’ve probably heard of these. You can book them on United.com
ZFV is the 30th street train station in downtown Philadelphia. United sells tickets from ZFV to Newark on Amtrak and then you check in your luggage for your flight at Newark. On the return you collect your luggage at Newark baggage claim and then take the train with your luggage onto ZFV station.
For a flight to Los Angeles you would book a ticket on United.com for ZFV-LAX which would involve the train ticket and then a nonstop flight from Newark to Los Angeles.
Similar to hidden-city ticketing, the airlines don’t particularly appreciate those who miss segments and one-way tickets are a good idea. If you decide to skip train segments it will be at your own risk!
A one-way fare nonstop from Kansas City to Newark is over $400 but Kansas City to ZFV via Newark is $88.45 with tax.
For example, current one-way sale fares with tax to or from ZFV and:
-S. Antonio, $87
-Kansas City, $89
-Las Vegas, $101
-Los Angeles, $107
-Portland, OR, $110
-S. Diego, $110