Yes. At least for the tickets I buy, fares seem to fluctuate wildly and rapidly. I had my eye on a ticket home for Thanksgiving recently, and it had climbed from ~$500 to almost $800 over a few weeks. When it suddenly dropped to $560, I bought. The next day, it was up to $620 or $650 again.

Last year I bought a flight on DL that was $560 at 9am. At 6pm, it was $380 and I bought it. By 9pm, it was back at the original $560.

Some of the most interesting threads in here are the ones with the pilots, FAs, GAs, etc. I'd love to see one with the people who set prices, or design the systems that do, so they could explain it to me!