yes, pretty much the same. a couple differences...use a little bigger seam (i use a 1/2" seam allowance when working with flannel) it tends to fray a little more because it has a looser-weave. you may have to adjust pattern measurements.
and if it is (thin/flimsy) a spray of starch or sizing will make it easier to cut straight.
flannel washes up wonderfully soft and fluffy!