I think Carlsbad hat is knit flat but I knit this in the round
Cast on 170 stitches Size 0 needles

Waste yarn knit 4-5 rows then switched to main color

28 rows grey then
4 rows of black stripe, then
4 rows grey stripe then
12 rows of second black stripe ( 48 total)
then approx 23 rows grey (60 rows total)

For decreasing, stitches were divided into 6 equal sections of 28 stitches each. (I had to reduce 2 random stitches from 170 to 168) then began decreases:
SSK on one side of each marker and k2tog on other side of each marker then 2 rows plain.

So: decrease row then 2 rows plain
then decrease row then 2 rows plain for 3 times or 4 times
then every other row a decrease row then finally
K2tog at the very last to reduce down to 10 or 12 stitches

Decreases occurred over a total of about 26 rows

I offered to make little mini ear flaps to make sure that his ears are completely covered but he didn’t want them.

I got rid of the waste yarn rows at the bottom and did a purl turning row then knit a black liner band in stockinette (about 14 rows ) with my son’s name on the inside band.

I knit my son’s name in stranded work using Sockmatician’s Intarsia in the round technique (Strandtarsia) of slipping stitches and knitting back on every other row when the contrast yarn is at the wrong end.

Sewed the liner band down with a whip stitch.

I made a little tag out of some fake leather fabric and silver marker and put his initials on it with an Arts and Crafts font.

My sons head is 24” circ and 17” from bottom of ear lobe to bottom of earlobe across the top of the head

Both of my sons like hats to come down and completely cover the ears which is why I often do a provisional cast on or a waste yarn cast on so I can easily adjust the length if the hat is too short.