They didn't, but they were dropped from high up enough that they were visible for considerable distance. Parachute flares are bright. Keep in mind they weren't dropped over, or even near, Phoenix. Just within line of sight until they dropped under the mountain chain's horizon.)

A few nights ago, I saw a UFO. It blinked like it was really close, it hovered (or seemed to), and generally behaved unusually.

I concluded that it was the local air service on its regular run and, for some reason or another, had to circle the airport. The airport is 24kms (I'm guessing about 18 miles) away and in the right direction of what I'd seen. So when it was coming towards me, or going away, it seemed stationary. When it was going laterally, it was doing so slowly enough that the motion wasn't obvious.

I found out this morning, however, that there was another skidoo accident at some point this weekend. (I don't have details yet.) It stretches probability a bit, but what I saw might have been a search and rescue flight circling a lot closer.

My point is this: identifying objects at night seems intuitive, but really isn't. We're not good at telling size, distance, and altitude of objects we can't fully see, even when we have decent reference points for comparison.

Drop objects in formation, they'll fall in formation. Basic high school physics.

They didn't stay up for several hours, although parachute flares dropped from a high altitude do stay up longer than most people might expect.

[edit]: I should also point out that "I saw the ISS go by around 9pm" and "Huh, I saw it too, but around 10pm" doesn't mean the ISS was visible for an hour. It means one or both eyewitness reports incorrectly guestimated the time, misremembered the event on later retelling, misidentified another satellite for the ISS, or one or both is outright lying.

Especially when the relevant schedules for that night clearly show the ISS passing at 7:45pm and overhead for two minutes.

Can't help you there. Only you can figure out exactly how you got misinformed. I'd suggest it may have had something to do with insufficient skepticism when reading web pages written by people with pro-UFO axes to grind.

The world is under no obligation to conform itself to your doubts.

__________________
[Dr. Horrible]___________________________[Penny]
Listen close to everybody's heart________And you believe there's good in everybody's heart
And hear that breaking sound_____________Keep it safe and sound
Hopes and dreams are shattering apart____With hope you can do your part
And crashing to the ground_______________To turn a life around