Surely this is some setting that is wrong, but what?? I trying to bend an extruded plane using the curve modifier, but as soon as I select the bezier curve in the modifier, I lose all dimensions of the plane! Top down ortho of plane & bezier curve before modifier
There was a scaling problem (even though I applied scaling & rotation) but I couldn't find the Transform > Radius that Ramos described. I found that if I zoomed in far enough, what I thought was a line was the horribly deformed extruded plane. I tried numerous re-scaling of both the plane & the curve, and with the hint that Mr Zak supplied, went to the Bezier curve's shape properties, and unchecked 'radius' (path/curve deform) and set Minimum's Smooth (Twisting) value from 0 to 6.00. Mostly by luck(?) I got the desired results. Mission accomplished! Thanks all.
It is possible to get a flat path using only a curve object, by setting the extrude property. You can also add a solidify modifier to give it some thickness.
The extrusion may not align the way you want at first, adjust the tilt to get it right, which can be found in the properties region N. You can use ⎈ CtrlT to adjust the tilt interactively.
If you want a mesh object after you have created your path, ⎇ AltC->Mesh From Curve will turn it into a mesh.