How To: Replace the SSD in your MacBook Air 13" (Early 2015) - YouTube
MacBook Air 11" Early 2015 SSD Replacement - iFixit Repair Guide
Amazon.com: 256GB SSD Hard Drive for Apple MacBook Pro Air 11" 13" 15" A1502 A1398 A1465 A1466 (Late 2013-2015) / OSX Sierra/Mac Pro A1481 : Electronics
Teardown Reveals New 13-Inch MacBook Air SSD is Nearly Twice as Fast as SSD in New 11-Inch MacBook Air - MacRumors