A megalopolis isn't characterized by a placename and an airport. It's characterized by continuous development. You can drive from Ventura to Yucaipa to to Temecula to Rosarito Beach in Mexico, and the only time you'd need to get a mile away from of high-density development is 5 miles of I-15 in a mountain pass, or 10 miles of coastal highway, both to span the Santa Ana Mountains (property of the US Forest Service / Cleveland National Forest for the most part).
The Los Angeles Conurbation is about to swallow the northern Imperial Valley as well, because the I-10 corridor is made up of flat sandy dirt that could be a suburban back yard.
The Los Angeles Conurbation is about to swallow the northern Imperial Valley as well, because the I-10 corridor is made up of flat sandy dirt that could be a suburban back yard.