2019-09-30 - Bakersfield?, CA - Rectangle

I was on a 737 flight from San Jose, CA, (SJC) southbound to Burbank, CA (BUR). We were airborne at about 4:50-ish PM. Pilot stated right before take-off that we’d be going up to 31,000 ft and we would in the air for 43 minutes. We were over the coastal mountains following the San Andreas fault. About halfway, I could see the highway 41 and 46 split (were James Dean died). Minutes later, I saw this glowing object across the San Joaquin Valley to the southeast. It appeared to be at mountain ridge level. I guess that would be the southern end of the Sierra Nevada range. I would estimate that it was whatever the mountains are due east of Bakersfield. The object was rectangular and either glowed, or reflected the sun. It had a red color to it, like if sun was reflecting off of red colored foil. The size had to be huge. I’m looking at it from quite a distance over on the coast range side of the valley. The shape looked like one of those rectangular banners being pulled by an airplane over events. But since it appeared to be so far away, it would not be possible for it to be that big. My estimate would be a couple of miles in length. As I tried to get my phone out to record, the “glowing/reflectiveness” of it would slowly fade in or out. I tried to record it on 2 separate devices but none of them came out. After observing this for about 10 minutes, it stopped and the plane veered to the right and went over the mountains above Santa Barbara and Ventura. I checked to see if perhaps it was a forest fire and I happened to just catch the moment when the bright flames crested the mountains, but could not find such news. The horizon was hazy, but there wasn’t any sign of smoke from a fire.