The flags column is undocumented. However if you poke around on the net, you'll find places where people have taken a stab at documenting them. Here's one shor list I found:
Append = 64
Crosstab = 16
Data-Definition = 96
Delete = 32
Deleted or temp ( prefixed with ~) = 3
Hidden = 8
Linked Table= 2097152
Make-Table = 80
MSys Table (w/o read permission) = 2
MSys Table (w/ read permission) = -2147483648
Select Query or standard table = 0
Union = 128
Update = 48
As you can see, most futher define the type of object. For what your doing, I can't see why you'd want to use the flag column. Checking the type column for 3 will get you all the tables.
JimD.