FOUR SIREN ALERT: Strange Aircraft In Texas

This is a four siren alert:

I living in Dallas, TX. I was out walking my dog this evening when I spotted four very unusual and silent aircraft heading North East from South West.

First, I have a PPL and a good working knowledge of general aviation. I know there are two major airports within 12 miles of my location, but I am familiar with the Ingress and Egress routes that commercial traffic takes both in and out of dfw and love field. These aircaft were not on any known approach vector in or out of either airport.

So what made them strange.

1. They looked to be about the size of a 737 but The wings on these aircraft were swept back about 60 degrees. I'm guaging this from the the lights I saw on the craft.

2. They were completely silent.

3. They were moving faster than any commercial aircraft would movie at that altitude (I am guessing they were at about 3k feet agl) in this area.

No, I don't have photos. As I said I was out with the dog and didn't have access to a camera. And it was so dark anyway all I would have captured would have been blown out lights.

Very strange. If anyone else sees any aircraft fitting this description this evening please post to this thread. Thank you.