Interplanetary mission velocity change and time of flight using Python (example used is outbound leg to Mars):

#!/usr/bin/env python3
import sys
from math import sqrt, pi, radians, sin
muP, muD, r1, rp1, muA, r2, rp2, inc = map(float, sys.argv[1:])
a = (r1 + r2) / 2.0
tof = pi * sqrt(a**3 / muP)
v1 = sqrt(muP / r1)
v2 = sqrt(muP / r2)
vt1 = sqrt(muP * (2.0 / r1 - 1.0 / a))
vt2 = sqrt(muP * (2.0 / r2 - 1.0 / a))
vinf1 = abs(vt1 - v1)
vinf2 = abs(v2 - vt2)
vc1 = sqrt(muD / rp1)
vp1 = sqrt(vinf1**2 + 2.0 * muD / rp1)
dv1 = vp1 - vc1
vc2 = sqrt(muA / rp2)
vp2 = sqrt(vinf2**2 + 2.0 * muA / rp2)
dv2 = vp2 - vc2
plane_speed = min(vt1, vt2)
plane = 2.0 * plane_speed * sin(radians(inc) / 2.0)
print(f"Transfer time   {tof/86400:12.3f}    days")
print(f"Injection Δv       {dv1:12.6f} km/s")
print(f"Capture Δv         {dv2:12.6f} km/s")
print()
print(f"Best case total Δv {dv1+dv2:12.6f} km/s")
print(f"Plane change       {plane  :12.6f} km/s")
print(f"Worst case total Δv{dv1+dv2+plane:12.6f} km/s")