Solid line = floor (spellings that unambiguously belong to the group). Shaded band up to the dashed edge = ceiling (the most it could reach if every ambiguous spelling counted here).
Travis is now well below its former popularity. All-time it's been given to 310,687 U.S. babies, the 761st most common name by sound today, peaking at 11,575 in 1989, with 732 in 2025.
Travis has no common alternate spellings by sound.
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).