Formation on 5 lights

I was looking at the sky and suddenly I saw a formation of lights travelling from East to west ( North West) it went over our building. it was a formation of 5 lights . 2 yellow lights at front and 2 yellow lights at side( slightly at back ) and one red light at the back side of front two lights. That thing had humming sound like aeroplane. it wasn't flying at higher altitude. That formation was stable lights ( no blinking lights as aeroplane) . we have airport near, about 30km away. so I see aeroplanes every day and I am sure what I saw wasn't an aeroplane. It was bigger in size than an aeroplane flying at that altitude. If it was an aeroplane of that size and flying at that altitude it could have definitely made really loud noise. But that formation wasn't making very loud sound. whenever I see an aeroplane coming from the distance they look like single point of light and when they come near I can see its various blinking lights. But this thing was from start to end looks like a formation and with stable, non blinking lights . And I tried to take pictures and videos of it, but somehow my phone camera glitched at that particular time . Everything else of my phone camera was working except capture button.